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1. A Review of the Stable Isotope Bio-geochemistry of the Global Silicon Cycle and Its Associated Trace Elements

Author

Jill N. Sutton, Luc André, Damien Cardinal, Daniel J. Conley, Gregory F. de Souza, Jonathan Dean, Justin Dodd, Claudia Ehlert, Michael J. Ellwood, Patrick J. Frings, Patricia Grasse, Katharine Hendry, Melanie J. Leng, Panagiotis Michalopoulos, Virginia N. Panizzo, and George E. A. Swann

Subjects
C – N – O - Si isotopes, biogenic silica, element/Si ratios, biogeochemical cycles, silicon, Science
Abstract

Silicon (Si) is the second most abundant element in the Earth's crust and is an important nutrient in the ocean. The global Si cycle plays a critical role in regulating primary productivity and carbon cycling on the continents and in the oceans. Development of the analytical tools used to study the sources, sinks, and fluxes of the global Si cycle (e.g., elemental and stable isotope ratio data for Ge, Si, Zn, etc.) have recently led to major advances in our understanding of the mechanisms and processes that constrain the cycling of Si in the modern environment and in the past. Here, we provide background on the geochemical tools that are available for studying the Si cycle and highlight our current understanding of the marine, freshwater and terrestrial systems. We place emphasis on the geochemistry (e.g., Al/Si, Ge/Si, Zn/Si, δ13C, δ15N, δ18O, δ30Si) of dissolved and biogenic Si, present case studies, such as the Silicic Acid Leakage Hypothesis, and discuss challenges associated with the development of these environmental proxies for the global Si cycle. We also discuss how each system within the global Si cycle might change over time (i.e., sources, sinks, and processes) and the potential technical and conceptual limitations that need to be considered for future studies.

Published
2018
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2. Interannual variability in particulate organic matter associated with physical forcing in the central Arabian Sea assessed from (stable) carbon and nitrogen isotopes

Author

Saumya Silori, Haimanti Biswas, and Damien Cardinal

Abstract

The biogeochemistry of the Arabian Sea, the northwestern part of the Indian Ocean, is directly impacted by monsoonal wind reversal and is an area of strong ocean-atmospheric interaction. During the summer monsoon, coastal as well as open ocean upwelling occurs in the western, southeastern, and central parts of the Arabian Sea. The highest primary productivity rates are documented in these areas compared to the global oceans. Phytoplankton-derived particulate organic matter (POM) [Particulate organic carbon (POC) and nitrogen (PN)] play a central role in supporting the food chain as well as carbon export flux to the deep sea. Hence understanding the dynamics of POM concentrations and its stable carbon (δ13CPOC) and nitrogen (δ15NPN) isotopic ratios are important in delineating its sources and recycling. However, such studies are scarce from the Indian Ocean region. Here we present the first study describing the POM dynamics during the summer monsoon from the central Arabian Sea, addressing the interannual variability. We studied the monsoonal changes in POM and its isotopic signatures in the central Arabian Sea (21–11°N; 64°E) during August 2017 and 2018. A strong, low-lying atmospheric jet (Findlater Jet) blows across the basin during the southwest (SW) monsoon. Positive wind stress curl resulted in “open ocean upwelling” to the north of the jet’s axis, characterized by substantially shallower Mixed Layers Depths (MLDs) and higher POM contents relative to the jet’s axis and its south. The highest wind speeds were observed in the center of the transect due to the presence of the jet’s axis. And the negative curl to the south of the jet’s axis resulted in downwelling and, consequently, the deepest MLDs. The molar ratio between POC and PN (6.2 ± 1.9 in 2017; 6.4 ± 0.9 in 2018) was close to the canonical Redfield ratio (6.63). The δ13CPOC values (−26.3 ± 1.4‰ in 2017; 25.5 ± 1.4‰ in 2018) exhibited typical marine signature and a noticeable inter-annual difference. Relatively higher δ15NPN values in the north (7.68 ± 2.6‰ in 2017; 9.24 ± 3‰ in 2018) indicated the uptake of regenerated dissolved inorganic nitrogen from the oxygen minimum zone (OMZ). The lower δ15NPN values along the jet’s axis and to its south were attributed to the eastward advection of upwelled waters from the western Arabian Sea. Higher wind speeds and jet-induced wind stress curl in 2018 resulted in lower sea surface temperatures (SST) and higher nutrient concentrations. Despite the higher nutrient availability in 2018, POC contents did not exceed the values in 2017. However, considering the total nitrogen consumption (according to C:N: P = 106:16:1), the potential POC development in 2018 could be double the value in 2017. The interannual differences in SW monsoon onset and wind speeds seemed to directly control the nutrient supply, affecting plankton community structure and POM variability. Thus, any future changes in the physical forcing may directly influence the POC pool and consequent export flux to the mesopelagic.

Published
2023
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4. Interannual variability in particulate organic matter distribution and its carbon stable isotope signatures from the western Indian shelf waters

Author

Saumya Silori, Haimanti Biswas, Mintu Chowdhury, Diksha Sharma, Mandeng-Yogo Magloire, and Damien Cardinal

Subjects
Carbon Isotopes, Environmental Engineering, Nitrogen Isotopes, Phytoplankton, Environmental Chemistry, Water, Particulate Matter, Pollution, Waste Management and Disposal, Carbon, Environmental Monitoring
Abstract

Particulate organic carbon and nitrogen (POC, PN, collectively particulate organic matter, POM) and the stable isotopic signature of POC (δ

Published
2022

5. Phytoplanktonic response to simulated volcanic and desert dust deposition events in the South Indian and Southern Oceans

Author

Nicolas Metzl, Carla Geisen, Dominique Marie, Pierre Delmelle, Céline Ridame, Claire Lo Monaco, Emilie Journet, Rawaa Ammar, Joelle Kombo, Damien Cardinal, UCL - SST/ELI - Earth and Life Institute, Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Earth and Life Institute - Environmental Sciences (ELIE), Université Catholique de Louvain = Catholic University of Louvain (UCL), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), LEFE (Les Enveloppes Fluides et l'Environnement) through BISOU and ITALIANO, DADDY project supported by IPSL, Adaptation et diversité en milieu marin (AD2M), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Station biologique de Roscoff (SBR)

Subjects
Biogeochemical cycle, geography, geography.geographical_feature_category, fungi, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Aquatic Science, Oceanography, complex mixtures, ocean, Indian ocean, iron, Volcano, Phytoplankton, volcanic ash, phytoplankton, Environmental science, Microcosm, Deposition (chemistry), Desert dust
Abstract

International audience; Contrasting concentrations of macronutrients and micronutrients induce different nutrient limitations of the oceanic productivity and shape the composition of the phytoplankton communities of the South Indian Ocean and Indian sector of the Southern Ocean. o assess the phytoplankton response to nutrient release by desert dust and volcanic ash aerosols in these distinct biogeochemical regions, we conducted microcosm incubation experiments. A dry or wet deposition of either dust from Patagonia or ash from the Icelandic volcano Eyjafjallajökull or dissolved nutrients (Si, Fe, N and/or P) were added to trace metal clean incubations of surface seawater collected from five stations. These deposition experiments enabled the measurement of the biological response along with solubility calculations of nutrients. Both types of aerosols alleviated the iron deficiency occurring in the Southern Ocean during austral summer and resulted in a 24–110% enhancement of the primary production, depending on the station. The release of dissolved silicon may also have contributed to this response, although to a lesser extent, whereas neither the dust nor the ash relieved the nitrogen limitation in the low-nutrient and low-chlorophyll area. Diatom growth was responsible for 40% to 100% of the algal biomass increase within the responding stations, depending on the region and aerosol type. The high particle concentrations that are characteristic of ash deposition following volcanic eruptions may be of equal or higher importance to phytoplankton compared to desert dust, despite ashes' lower nutrient solubility to the ocean.

Published
2022
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6. A silicon isotopic perspective on the contribution of diagenesis to the sedimentary silicon budget in the Southern Ocean

Author

Ivia Closset, Mark A. Brzezinski, Damien Cardinal, Arnaud Dapoigny, Janice L. Jones, Rebecca S. Robinson, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Department of Ecology, Evolution and Marine Biology [Santa Barbara] (EEMB), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Graduate School of Oceanography [Narragansett], and University of Rhode Island (URI)

Subjects
Silicon cycle, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], Silicon stable isotopes, Southern Ocean, Early diagenesis, Benthic nutrient fluxes
Abstract

International audience; Diatoms are known to fractionate silicon isotopes during the formation of their frustules causing the silicon isotopic composition of biogenic silica to track the degree of silicic acid consumption in surface waters. Despite a growing body of work that uses this proxy to reconstruct past changes in silicic acid utilization, the understanding of the benthic silicon cycle, particularly the identification and quantification of the processes that potentially alter the silicon isotopic composition of biogenic silica during early diagenesis is still lacking. We investigated these processes by comparing the silicon isotopic composition of pore water silicic acid, biogenic silica and, for the first time, lithogenic silica from five sediment cores collected in the deep basin of the Southern Ocean representing a diversity of sedimentation regimes. Silicic acid concentrations and the isotopic composition of Southern Ocean pore waters were the result of a dynamic balance between the dissolution of biogenic silica, reactive lithogenic silica phases and Si re-precipitation with the relative importance of each processes differing significantly between regions. The results are consistent with the formation of authigenic alumino-silicates derived from dissolved biogenic silica in the Sub-Antarctic Zone and in the Antarctic Zone (on average 12 ± 5% and 17 ± 13%, respectively). Since this latter process can fractionate silicon isotopes, this implies that, even if the silicon isotopic composition of diatoms preserved in the sediments is a reliable proxy for silicic acid utilization in the past ocean, care must be taken to extract a clean biogenic silica phase free of authigenic clays and lithogenic phases from sediments to eliminate this potential bias when interpreting isotopic records.

Published
2022
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7. Bioactive trace metals and their isotopes as paleoproductivity proxies: An assessment using GEOTRACES‐era data

Author

Tristan Horner, Susan Little, Tim Conway, Jesse Farmer, Jennifer Hertzberg, David Janssen, Alastair Lough, Jennifer McKay, Allyson Tessin, Stephen Galer, Sam Jaccard, Francois Lacan, Adina Paytan, Kathrin Wuttig, Clara Bolton, Eva Calvo, Damien Cardinal, Thibault de Garidel-Thoron, Susanne Fietz, Katharine Hendry, Franco Marcantonio, Patrick Rafter, Haojia Ren, Christopher Somes, Jill Sutton, Adi Torfstein, Gisela Winckler, Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Birkbeck College [University of London], College of Marine Science [St Petersburg, FL], University of South Florida [Tampa] (USF), Department of Geosciences [Princeton], Princeton University, Department of Ocean, Earth and Atmospheric Sciences [Norfolk], Old Dominion University [Norfolk] (ODU), Oeschger Centre for Climate Change Research (OCCR), University of Bern, College of Earth, Ocean and Atmospheric Sciences [Corvallis] (CEOAS), Oregon State University (OSU), Kentucky State University, Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institute of Marine Sciences, Long Marine Laboratory, University of California [Santa Cruz] (UCSC), University of California-University of California, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Science Foundation (US), Swiss Academy of Sciences, Natural Environment Research Council (UK), University of South Florida, Max Planck Society, Agencia Estatal de Investigación (España), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), GEOTRACES, and PAGES Global Charcoal Database

Subjects
0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Geotraces, chemistry.chemical_element, 010502 geochemistry & geophysics, 01 natural sciences, 7. Clean energy, Atmosphere, Paleoceanography, Phytoplankton, marine chemistry, Environmental Chemistry, 14. Life underwater, General Environmental Science, Global and Planetary Change, 0105 earth and related environmental sciences, Isotope, 010604 marine biology & hydrobiology, Biological pump, biogeochemical cycles, Seafloor spreading, Oceanography, chemistry, 13. Climate action, micronutrients, [SDE]Environmental Sciences, paleoceanography, phytoplankton, Environmental science, Carbon, biological pump
Abstract

86 pages, 33 figures, 2 tables, 1 appendix.-- Data Availability Statement: The majority of the dissolved data were sourced from the GEOTRACES Intermediate Data Products in 2014 (Mawji et al., 2015) and 2017 (Schlitzer et al., 2018), and citations to the primary data sources are given in the caption for each figure. Data sources for Figure 1 are given below. Figure 1: Iron: Conway & John, 2014a (Atlantic); Conway & John, 2015a (Pacific); Abadie et al., 2017 (Southern). Zinc: Conway & John, 2014b (Atlantic); Conway & John, 2015a (Pacific); R. M. Wang et al., 2019 (Southern). Copper: Little et al., 2018 (Atlantic); Takano et al., 2017 (Pacific); Boye et al., 2012 (Southern). Cadmium: Conway and John, 2015b (Atlantic); Conway & John, 2015a (Pacific); Abouchami et al., 2014 (Southern). Molybdenum: Nakagawa et al., 2012 (all basins). Barium: Bates et al., 2017 (Atlantic); Geyman et al., 2019 (Pacific); Hsieh & Henderson, 2017 (Southern). Nickel: Archer et al., 2020 (Atlantic); Takano et al., 2017 (Pacific); R. M. Wang et al., 2019 (Southern). Chromium: Goring-Harford et al., 2018 (Atlantic); Moos & Boyle, 2019 (Pacific); Rickli et al., 2019 (Southern). Silver: Fischer et al., 2018 (Pacific); Boye et al., 2012 (Southern), Phytoplankton productivity and export sequester climatically significant quantities of atmospheric carbon dioxide as particulate organic carbon through a suite of processes termed the biological pump. Constraining how the biological pump operated in the past is important for understanding past atmospheric carbon dioxide concentrations and Earth's climate history. However, reconstructing the history of the biological pump requires proxies. Due to their intimate association with biological processes, several bioactive trace metals and their isotopes are potential proxies for past phytoplankton productivity, including iron, zinc, copper, cadmium, molybdenum, barium, nickel, chromium, and silver. Here, we review the oceanic distributions, driving processes, and depositional archives for these nine metals and their isotopes based on GEOTRACES-era datasets. We offer an assessment of the overall maturity of each isotope system to serve as a proxy for diagnosing aspects of past ocean productivity and identify priorities for future research. This assessment reveals that cadmium, barium, nickel, and chromium isotopes offer the most promise as tracers of paleoproductivity, whereas iron, zinc, copper, and molybdenum do not. Too little is known about silver to make a confident determination. Intriguingly, the trace metals that are least sensitive to productivity may be used to track other aspects of ocean chemistry, such as nutrient sources, particle scavenging, organic complexation, and ocean redox state. These complementary sensitivities suggest new opportunities for combining perspectives from multiple proxies that will ultimately enable painting a more complete picture of marine paleoproductivity, biogeochemical cycles, and Earth's climate history, This contribution grew (and grew) out of a joint workshop between GEOTRACES and Past Global Changes (PAGES) held in Aix-en-Provence in December 2018. The workshop was funded by the U.S. National Science Foundation (NSF) through the GEOTRACES program, the international PAGES project, which received support from the Swiss Academy of Sciences and NSF, and the French program Les Envelopes Fluides et l'Environnement. [...] T. J. Horner acknowledges support from NSF; S. H. Little from the UK Natural Environment Research Council (NE/P018181/1); T. M. Conway from the University of South Florida; and, J. R. Farmer from the Max Planck Society, the Tuttle Fund of the Department of Geosciences of Princeton University, the Grand Challenges Program of the Princeton Environmental Institute, and the Andlinger Center for Energy and the Environment of Princeton University. [...] With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

Published
2021
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8. Particulate organic matter dynamics and its isotopic signatures (δ13CPOC and δ15NPN) in relation to physical forcing in the central Arabian Sea during SW monsoon (2017–2018)

Author

Haimanti Biswas, Damien Cardinal, Mintu Chowdhury, M. Mandeng-Yogo, Diksha Sharma, Saumya Silori, CSIR National Institute of Oceanography [India] (NIO), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Variabilité à long terme du climat de l'océan (VALCO), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
Environmental Engineering, 010504 meteorology & atmospheric sciences, Mesopelagic zone, Flux, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010501 environmental sciences, Plankton, Oxygen minimum zone, Monsoon, Atmospheric sciences, 01 natural sciences, Pollution, Sea surface temperature, 13. Climate action, Environmental Chemistry, Environmental science, Upwelling, 14. Life underwater, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Redfield ratio
Abstract

Monsoonal changes in particulate organic matter (POM) and its isotopic signatures (δ13CPOC and δ15NPN) were studied (Aug 2017 and 2018) in the central Arabian Sea (21–11°N 64°E) . A low-level atmospheric jet (Findlater Jet) forms during the south-west (SW) monsoon and results in “open ocean upwelling” to the north of the jet's axis. Higher wind speed and jet-induced wind stress curl coupled with low sea surface temperature (SST) and higher nutrients were noticed in 2018 than in 2017. The region to the north of the jet was characterized by substantially shallower Mixed Layers Depths (MLDs) and higher POM contents relative to the jet's axis and southern stations. The molar ratio between particulate organic carbon (POC) and nitrogen (PN) (6.2 ± 1.9in 2017; 6.4 ± 0.9 in 2018) was very close to the canonical Redfield ratio (6.63). The δ13CPOC values (−26.3 ± 1.4‰ in 2017; 25.5 ± 1.4‰ in 2018) exhibited typical marine signature reported from this area and revealed a noticeable inter-annual difference. Relatively higher δ15NPN values noticed in the north (7.68 ± 2.6‰ in 2017; 9.24 ± 3‰ in 2018) indicated regenerated dissolved inorganic nitrogen coming from the oxygen minimum zone (OMZ) into the well-lit zone. The lower δ15NPN values along the jet axis and south of it were attributed to lateral advection of nitrogen from the Somali upwelling. Despite the higher nutrient availability, POC contents in 2018 did not exceed the values in 2017. Considering the total consumption of nitrogen (according to C:N: P = 106:16:1), the potential POC development in 2018 could be double the value in 2017. The interannual differences in SW monsoon onset and wind speed seem to directly control the nutrient supply, affecting plankton community structure and POM variability. Thus, any future change in the physical forcing may directly influence the POC pool and consequent export flux to the mesopelagic.

Published
2021
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9. Tracing terrestrial versus marine sources of dissolved organic carbon in the largest monsoonal Godavari estuary in India using stable carbon isotopes

Author

Siva kiran kumar Busala, V.V.S.S. Sarma, Damien Cardinal, CSIR National Institute of Oceanography [India] (NIO), Academy of Scientific and Innovative Research [Ghaziabad, India] (AcSIR), Partenaires INRAE, Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
[SDU]Sciences of the Universe [physics], Aquatic Science, Oceanography
Abstract

International audience; To examine the sources of dissolved organic carbon (DOC) and its modifications within the estuary, time-series sampling was conducted at 10 stations covering the entire salinity range in the Godavari estuary. The salinity of the upper estuary was close to zero and increased to 32 at the lower estuary during the dry period whereas the entire estuary was filled with fresh water during the wet period. The estuary received a high concentration of suspended particulate matter (SPM) during the wet compared to the dry period. The concentration of DOC and DON was 1.5-3 times higher during the wet than dry period with DOC: DON ratios of 5-20. The depleted isotopic composition of DOC (δ13CDOC) was observed during the dry period in the upper estuary and it was enriched towards the lower estuary suggesting that terrestrial organic matter (mainly C3 plant) is the source in the upper and marine sources in the lower estuary. Highly enriched δ13CDOC values were noticed during July-August, which was associated with peak discharge, suggesting that soil organic matter may be a potential source. Enhanced phytoplankton biomass was observed during October-November associated with depleted δ13CDOC from that peak discharge period suggesting DOC released by phytoplankton bloom by phytoplankton bloom (Merismopedia sp.) by freshwater algae may be contributed significantly to the DOC pool. Based on the deviation from the simple mixing line between the upper and lower estuary, the removal of DOC seems to be occurring through microbial decomposition and photo-oxidation during the dry period. The modification of DOC within the estuary may be minimal due to the low residence of water (

Published
2022
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10. Contrasting phytoplankton and biogeochemical functioning in the eastern Arabian Sea shelf waters recorded by carbon isotopes (SW monsoon)

Author

Saumya Silori, Debasmita Bandyopadhyay, M. Mandeng-Yogo, Jayu Narvekar, Diksha Sharma, Aziz Ur Rahman Shaik, Haimanti Biswas, Mintu Chowdhury, Damien Cardinal, CSIR National Institute of Oceanography [India] (NIO), National Center for Coastal Research, Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Variabilité à long terme du climat de l'océan (VALCO), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Eastern Arabian Sea, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Oceanography, Monsoon, 01 natural sciences, Isotopic signature, Nanophytoplankton, Phytoplankton, Environmental Chemistry, Organic matter, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, POC, chemistry.chemical_classification, Upwelling, 010604 marine biology & hydrobiology, Biogeochemistry, General Chemistry, 15. Life on land, Western Indian shelf, chemistry, SW monsoon, 13. Climate action, Environmental science, δ13CPOC
Abstract

This study examines the relationship between the isotopic signature of phytoplankton-derived particulate organic matter (POM) (δ 13CPOC ) and estimates of growth rate and community composition along a north-south gradient in the western Indian shelf waters which possess contrasting biogeochemistry and mixed layers depths. The Eastern Arabian Sea/western Indian shelf turns highly productive due to the SW monsoon induced upwelling at its southern region and experiences drastic seasonal reversal. We have characterized the POM pool by quantifying Chl a , particulate organic carbon (POC) and particulate nitrogen (PN), C:N ratios, along with δ 13CPOC values during the SW Monsoon. The prevailing physicochemical features contrasted between the southern (8°N to 12°N) and northern (13°N to 21°N) stations. Close couplings between POC, PN, and Chla contents indicated the autochthonous nature of POM. Low temperature, shallow mixed layer depths (MLDs), high concentrations of nutrients, POM, and Chla, marked the upwelling signature in the south. Conversely, relatively higher temperatures, salinity, deeper mixed layers (MLs), lower concentrations of nutrients, POM, and Chla were evident at the northern stations. Five times higher POC concentrations were noticed in the south (65.5 ± 22.0 μmol L−1) than in the north (12.8± 5.4 μmol L−1) within the MLs. Phytoplankton community shift (based on marker pigment analysis) and the δ13CPOC values were closely coupled. The nutrient replete microphytoplankton (diatoms) dominated southern stations were associated with higher values of δ13CPOC (−23.0 ± 2.3‰) which was attributed to faster growth rate; conversely, the oligotrophic nitrogen-limited waters in the north dominated by pico and nanophytoplankton (haptophytes and cyanobacteria), were characterized by distinctly lower δ13CPOC values (−26.6 ± 0.9‰). Phytoplankton growth rates based on a model were consistent with this trend. Our results show that the autochthonous POC is the primary source of organic matter, and the contrasted biogeochemistry induced phytoplankton communities and their growth rates mostly governed the δ13CPOC variability in this region. However, the lower values in the subsurface waters at the south were likely to be influenced by light limitation and heterotrophy .

Published
2021
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11. Assessment of C, N and Si isotopes as tracers of past ocean nutrient and carbon cycling

Author

Jesse Farmer, Jennifer Hertzberg, Damien Cardinal, Susanne Fietz, Katharine Hendry, Sam Jaccard, Adina Paytan, Patrick Rafter, Haojia Ren, Christopher Somes, and Jill Sutton

Subjects
010504 meteorology & atmospheric sciences, 13. Climate action, 14. Life underwater, 010502 geochemistry & geophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2021
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14. Assessment of C, N and Si isotope tracers associated to past ocean productivity

Author

Susanne Fietz, Adina Paytan, Damien Cardinal, Jesse Farmer, Jennifer E. Hertzberg, Jill N. Sutton, Haojia Ren, Christopher J. Somes, Katharine R. Hendry, Samuel L Jaccard, and Patrick A. Rafter

Subjects
Atmosphere, chemistry, Productivity (ecology), Isotope, chemistry.chemical_element, Environmental science, Atmospheric sciences, Carbon
Abstract

Biological productivity in the ocean directly influences the partitioning of carbon between the atmosphere and ocean interior, thereby controlling the distributions of many elements and their isoto...

Published
2020
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15. Impact of desert and volcanic aerosol deposition on phytoplankton in the South Indian Ocean and Southern Ocean

Author

Carla Geisen, Celine Ridame, Emilie Journet, Benoit Caron, Dominique Marie, and Damien Cardinal

Abstract

The Southern Ocean is known to be the largest High Nutrient Low Chlorophyll (HNLC) area of the global ocean, where algal development is mainly limited by iron (Fe) deficiency, except in few naturally Fefertilized areas (e.g. around Kerguelen plateau). The availability of different nutrients is unevenly distributed in this area. Thus, northwards the polar front, nitrogen and phosphorus (N and P) concentrations are high, but the scarcity of silicon (Si) limits the growth of diatoms (HN-LSi-LC). Further North, the Southern Indian Ocean is characterized by macronutrient limitation and low primary production (LNLC).In these areas, atmospheric input could play a major role in the nutrient supply of primary producers. The main aim of this study is to assess the biological response of local phytoplankton communities to a deposition of two types of natural aerosols: desert dust and volcanic ash. Preliminary trace-metal clean laboratory experiments enabled us to quantify the abiotic dissolution of main macro- and micronutrients in dry and wet deposition mode of different natural aerosols of these types that yield us to choose Patagonia dust and ash from the Icelandic volcano Eyjafjallajökull for our experiment at sea.We set up a series of on-board trace-metal clean microcosm experiments in the contrasted biogeochemical conditions of the South Indian Ocean and Southern Ocean with addition of realistic amounts of dust and ash of respectively 2 and 25 mg.L-1. Experiments ran over 48 hours to evaluate the triggered primary production and cell abundances. Primary production was estimated by 13C spike and biogenic Si (bSi) uptake rates were assessed by 30Si spike. Parallel experiments with nutrient addition (dFe, DIP, DIN and dSi) along with flux cytometry for estimation of pico- and nanophytoplankton cells enabled us to determine which element(s) dissolved from the aerosols was responsible for the enhanced algal growth.The highest CO2 fixation rate of 50 mg.m-3.day-1 was found at the natural Fe fertilized Kerguelen plateau station. Dust, ash and Fe addition triggered primary production, and CO2 fixation doubled in these treatments. We recorded an enrichment of b30Si, indicating an increase of Si uptake rate, mostly stimulated by Fe addition. At the different HNLC stations (high N - low Si and high N - high Si), Fe and aerosol addition induced as well increased CO2 fixation. In the northern LNLC stations, algal growth was stimulated by nitrogen addition as expected, but Fe, Si and aerosol addition also triggered a biological response from Synechococcus cyanobacteria and pico- and nanoeukaryotes.Noteworthy, in most experiments the two contrasted aerosol types (desert dust and volcanic ash) at particle charges which varied over more than an order of magnitude triggered very similar biological responses in all of the sampled areas, even with distinct elementary and mineral compositions (e.g. the Icelandic volcano ash is 64 % amorphous and contains roughly twice the amount of Fe, P, Mn andZn compared to the Patagonian desert dust which is only 48 % amorphous).

Published
2020
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16. Assessing seasonal controls in silicon cycle and isotopic signatures of groundwater under anthropogenic stress in tropical watershed

Author

Benjamin Baud, Arnaud Dapoigny, Sarma Vedula Vss, Véronique Vaury, Damien Cardinal, Ramananda Chakrabarti, Laurent Ruiz, Jean Riotte, Busala Siva Kiran Kumar, and Sarath Pullyottum Kavil

Subjects
Anthropogenic stress, Hydrology, Watershed, Environmental science, Silicon cycle, Groundwater
Abstract

Intense irrigation along with extensive use of fertilizers significantly effects the hydrological and biogeochemical cycles in shallow aquifers. Land use changes associated with human activities are known to be a major controlling factor of the terrestrial silicon cycle, altering silicon fluxes to surface and groundwater. In the present study we determined dissolved silicon concentration (DSi) and δ30Si of shallow groundwater samples collected from bore wells and piezometers of two watersheds in Southern India under contrasting land use: one intensely cultivated (Berambadi) and one forested (Mule Hole).Intense groundwater irrigation in the Berambadi region leads to water table depletion, progressive salinization and occurrence of nitrate hotspots in groundwater. We collected groundwater samples during two periods, during the summer (dry) season in March and during the South-West monsoon season in August from both watersheds. DSi values ranged from 410 µM to 1487 µM, with a lower value during August sampling indicating dilution effects caused by monsoon precipitation. Mule Hole and Berambadi aquifer recharge mostly occurs through surface water percolation or from lateral flow. Groundwater composition thus exhibits seasonal variation depending on precipitation which can be traced using water isotopes (δ18O and δ2H). The depleted values in Berambadi groundwater (average δ18O of -2.99 ‰ and δ2H of -15.86 ‰) compared to forested watershed in Mule Hole indicate higher contribution from meteoric water likely due to quicker turnover resulting from continuous irrigation.Silicon isotope fractionation in natural waters is majorly controlled by soil-water interaction consisting in dissolution of primary minerals and formation of secondary minerals and also from biogenic sources and uptake. Preliminary results show no significant differences in δ30Si signatures in groundwater from the two watersheds (1.1 ± 0.3 ‰) in dry season despite higher and more variable DSi concentration in cultivated watershed (1100 ± 260 µM vs. 790 ± 120 µM for the forest). Assuming similar discharge, higher DSi concentration in Berambadi during both seasons indicates increased export/mobilization of Si into aquifer when compared to forested landscape.We will further refine our understanding of Si biogeochemistry in groundwater and the changes associated with land use by comparing the water and silicon isotopes with the germanium/silicon ratio and major element compositions in comparison with surface water data.

Published
2020
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17. Impacts of Zn and Cu enrichment under ocean acidification scenario on a phytoplankton community from tropical upwelling system

Author

Durbar Ray, Saumya Silori, Debasmita Bandyopadhyay, Haimanti Biswas, Damien Cardinal, Diksha Sharma, Magloire Mandeng-Yogo, Aziz Ur Rahman Shaik, CSIR National Institute of Oceanography [India] (NIO), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Variabilité à long terme du climat de l'océan (VALCO), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)

Subjects
0106 biological sciences, Nitzschia, India, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Aquatic Science, Oceanography, 010603 evolutionary biology, 01 natural sciences, Phytoplankton, Seawater, Trace metal, Arabian sea, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, Diatoms, Upwelling, biology, Chemistry, Ocean acidification, 010604 marine biology & hydrobiology, fungi, Chaetoceros, General Medicine, Hydrogen-Ion Concentration, biology.organism_classification, Pollution, Zinc, Diatom, 13. Climate action, Environmental chemistry, Bloom, Acids, Copper
Abstract

Increasing dissolution of CO2 in the surface ocean is rapidly decreasing its pH and changing carbon chemistry which is further affecting marine biota in several ways. Phytoplankton response studies under the combination of elevated CO2 and trace metals are rare. We have conducted two consecutive onboard incubation experiments (R. V. Sindhu Sadhana; August 2017) in the eastern Arabian Sea (SW coast of India) during an upwelling event. A nutrient enriched diatom bloom was initiated onboard and grown under ambient (approximate to 400 mu atm, A-CO2) and high CO 2 levels (approximate to 1000 patm; H-CO2) with different zinc (Zn; 1 nM) and copper (Cu) concentrations (1 nM, 2 nM and 8 nM). Phytoplankton community composition and the dominant genera were different during these two experiments. CO2 enrichment alone did not show any significant growth stimulating impact on the experimental community except enhanced cell density in the first experiment. Addition of Zn at A-CO2 level revealed no noticeable responses; whereas, the same treatment under H-CO2 level significantly reduced cell number. Considerably high protein content under H-CO2+Zn treatment was possibly counteracting Zn toxicity which also caused slower growth rate. Cu addition did not show any noticeable impact on growth and biomass production except increased protein content as well as decreased carbohydrate: protein ratio. This can be attributed to relatively higher protein synthesis than carbohydrate to alleviate oxidative stress generated by Cu. The centric diatom Chaetoceros and toxin producing pennate diatom Pseudo-nitzschia showed no significant response to either CO2 or Zn enrichment. Large centric diatom Leptocylindrus and Skeletonema responded positively to Zn addition in both CO2 levels. The former species showed the most sensitive response at the highest Cu and H-CO2 treatment; whereas, the pennate diatoms Mtzschia and Pseudo-nttzschia (toxigenic diatom) showed higher resilience under elevated CO2 and Cu levels. This observation indicated that in future ocean, increasing CO2 concentrations and trace metal pollution may potentially alter phytoplankton community structure and may facilitate toxigenic diatom bloom in the coastal waters.

Published
2020
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19. Corrigendum to 'Particulate organic matter dynamics and its isotopic signatures (δ13CPOC and δ15NPN) in relation to physical forcing in the central Arabian Sea during SW monsoon (2017–2018)' [Sci. Total Environ., 785 (2021) 1 – 15/147326]

Author

Damien Cardinal, Mintu Chowdhury, Magloire Mandeng-Yogo, Haimanti Biswas, Diksha Sharma, and Saumya Silori

Subjects
Environmental Engineering, Particulate organic matter, Environmental Chemistry, Environmental science, Forcing (mathematics), Monsoon, Atmospheric sciences, Pollution, Waste Management and Disposal
Published
2022
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20. New Insights Into Processes Controlling the δ30Si of Sinking Diatoms: A Seasonally Resolved Box Model Approach

Author

Thomas W. Trull, François Fripiat, Damien Cardinal, Ivia Closset, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, European Project: 294146,EC:FP7:PEOPLE,FP7-PEOPLE-2011-CIG,MUSICC(2011), University of California [Santa Barbara] (UCSB), University of California-University of California, Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)

Subjects
0106 biological sciences, Atmospheric Science, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Mixed layer, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Mineralogy, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Biogenic silica, 01 natural sciences, Deep sea, chemistry.chemical_compound, Flux (metallurgy), Environmental Chemistry, 14. Life underwater, Silicic acid, Dissolution, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, General Environmental Science, Global and Planetary Change, biology, 010604 marine biology & hydrobiology, biology.organism_classification, Diatom, chemistry, 13. Climate action, Environmental science
Abstract

In the Southern Ocean, the silicon (Si) biogeochemical cycle is dominated by processes such as the supply of Si into the surface waters, Si uptake into diatom frustules, and their subsequent dissolution and export. Due to the incomplete assimilation of the silicic acid pool (DSi) and isotopic fractionation during silicification, the Si isotopic composition (δ30Si) of biogenic silica (BSi) is closely linked to the degree of Si utilization in the mixed layer (ML). In this study, we combined modelling approaches and seasonal sediment trap records of δ30Si of exported BSi to investigate the magnitude, timing, and isotopic composition of the flux of siliceous particles transferred from the surface to the deep ocean. We implemented a box model to describe the temporal evolution of DSi and BSi concentrations and δ30Si in the ML and at depth. The model allows us to quantify fluxes of Si in and out of the ML associated with export, dissolution, and mixing. It highlights that the time‐integrated δ30Si of exported BSi measured in the sediments reflects the extent of DSi consumption at the time when net BSi production and diatom accumulation are maximal in the ML and confirms that the δ30Si of diatoms is a reliable proxy for past Si utilization.

Published
2019
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21. Unveiling the Si cycle using isotopes in an iron-fertilized zone of the Southern Ocean: from mixed-layer supply to export

Author

Mathieu Rembauville, Ivia Closset, François Thil, Stéphane Blain, Damien Cardinal, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Géochrononologie Traceurs Archéométrie (GEOTRAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), European Project: 294146,EC:FP7:PEOPLE,FP7-PEOPLE-2011-CIG,MUSICC(2011), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
Polar front, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Water mass, Biogeochemical cycle, Isopycnal, 010504 meteorology & atmospheric sciences, lcsh:QE1-996.5, lcsh:Life, Biogenic silica, 010502 geochemistry & geophysics, 01 natural sciences, lcsh:Geology, lcsh:QH501-531, Oceanography, Water column, 13. Climate action, lcsh:QH540-549.5, lcsh:Ecology, 14. Life underwater, Bloom, Surface water, Geology, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

International audience; A massive diatom bloom forms annually in the surface waters of the naturally iron-fertilized Kerguelen Plateau (Southern Ocean). In this study, silicon isotopic signatures (δ30Si) of silicic acid (DSi) and suspended bio-genic silica (BSi) were investigated through the whole water column with unprecedented spatial resolution, during the KEOPS-2 experiment (spring 2011). We used δ30Si measurements to track the sources of silicon that fuelled the bloom, and investigated the seasonal evolution of the Si bio-geochemical cycle in the iron-fertilized area. We compared the results from stations with various degrees of iron enrichment and bloom conditions to an HNLC reference station. Dissolved and particulate δ30 Si signatures were highly variable in the upper 500 m, reflecting the effect of intense silicon utilization in spring, while they were quite homogeneous in deeper waters. The Si isotopic and mass balance identified a unique Winter Water (WW) Si source for the iron-fertilized area that originated from southeast of the Kerguelen Plateau and spread northward. When the WW reached a retroflection of the Polar Front (PF), the δ30Si composition of the silicic acid pool became progressively heavier. This would result from sequential diapycnal and isopycnal mixings between the initial WW and ML water masses, highlighting the strong circulation of surface waters that defined this zone. When comparing the results from the two KEOPS expeditions , the relationship between DSi depletion, BSi production , and their isotopic composition appears decoupled in the iron-fertilized area. This seasonal decoupling could help to explain the low apparent fractionation factor observed in the ML at the end of summer. Taking into account these considerations , we refined the seasonal net BSi production in the ML of the iron-fertilized area to 3.0 ± 0.3 mol Si m−2 yr−1 , which was exclusively sustained by surface water phytoplankton populations. These insights confirm that the isotopic composition of dissolved and particulate silicon is a promising tool to improve our understanding of the Si biogeochemical cycle since the isotopic and mass balance allows resolution of processes in the Si cycle (i.e. uptake, dissolution , mixing).

Published
2016
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22. The GEOTRACES Intermediate Data Product 2017

Author

Thomas J. Browning, Hans-Jürgen Brumsack, Katharina Pahnke, Saeed Roshan, Stephanie Owens, Rosie Chance, Peter Croot, Steven van Heuven, Alison E. Hartman, Mercedes López-Lora, Pu Zhang, Heather A. Bouman, Géraldine Sarthou, François Lacan, Robyn E. Tuerena, José Marcus Godoy, Ester Garcia-Solsona, Steven L. Goldstein, Hans A. Slagter, Celia Venchiarutti, A. Russell Flegal, Emily Townsend, Ralph Till, Christopher T. Hayes, Melanie Gault-Ringold, Ros Watson, Peter N. Sedwick, Chandranath Basak, Bronwyn Wake, Loes J. A. Gerringa, Noriko Nakayama, Lars-Eric Heimbürger, Paul J. Morris, François Fripiat, Paul B. Henderson, Chris J. Daniels, Catherine Jeandel, Helen M. Snaith, Patrizia Ziveri, Toshitaka Gamo, Yanbin Lu, Oliver J. Lechtenfeld, Yingzhe Wu, Andreas Wisotzki, Hajime Obata, Cynthia Dumousseaud, Ashley T. Townsend, Sebastian Mieruch, Donna Cockwell, Laurent Bopp, Elena Masferrer Dodas, Bernhard Schnetger, J. K. Klar, Sunil K. Singh, Joaquin E. Chaves, Kuo-Fang Huang, Louise A. Zimmer, Laura F. Robinson, Michiel M Rutgers van der Loeff, Corey Archer, Feifei Deng, Karen Grissom, Robert Rember, Nicholas J. Hawco, Jingfeng Wu, Robert M. Sherrell, Rachel U. Shelley, Jan-Lukas Menzel Barraqueta, E. Malcolm S. Woodward, Fanny Chever, Yuichiro Kumamoto, Hélène Planquette, Dorothea Bauch, Frank Dehairs, Daniel C. Ohnemus, Akira Nishiuchi, Paul D. Quay, Sanjin Mehic, Zichen Xue, Maxi Castrillejo, Brian Peters, Michael J. Ellwood, Stephen R. Rintoul, Tobias Roeske, Jing Zhang, Gretchen J. Swarr, Peng Ho, Ken O. Buesseler, Gwenaelle Moncoiffe, Martin Frank, Maureen E. Auro, Abby Bull, David Kadko, Montserrat Roca-Martí, Maeve C. Lohan, Roulin Khondoker, Patricia Cámara Mor, Melissa Gilbert, Sebastian M. Vivancos, Erin E. Black, Santiago R. Gonzalez, Gideon M. Henderson, David J. Janssen, Sylvain Rigaud, Amandine Radic, Maxence Paul, Cyril Abadie, Ana Aguliar-Islas, Seth G. John, Marie Boye, Evgenia Ryabenko, Abigail E. Noble, Luke Bridgestock, Brian Duggan, Hisayuki Yoshikawa, Jun Nishioka, Kathrin Wuttig, Pieter van Beek, Jana Friedrich, Thomas M. Church, Maija Heller, Stephen J.G. Galer, Pier van der Merwe, Claire P. Till, Xin Yuan Zheng, Henning Fröllje, John Niedermiller, Howie D. Scher, Johnny Stutsman, Patricia Zunino, Christel S. Hassler, Ye Zhao, Tim M. Conway, William M. Landing, Yang Xiang, Katrin Bluhm, Maria T. Maldonado, Elena Chamizo, Sabrina Speich, Claudine H. Stirling, Guillaume Brissebrat, Matthew A. Charette, Jeremy E. Jacquot, Yu-Te Hsieh, Pinghe Cai, Ivia Closset, Yoshiki Sohrin, Ejin George, Jong-Mi Lee, Leopoldo D. Pena, Edward Mawji, Damien Cardinal, Catherine Pradoux, Martin Q. Fleisher, Virginie Sanial, Derek Vance, Craig A. Carlson, Pere Masqué, Katlin L. Bowman, Evaline M. van Weerlee, Oliver Baars, Ruifang C. Xie, María Villa-Alfageme, Hein J W de Baar, M. Alexandra Weigand, Tina van de Flierdt, J. Bown, Timothy C. Kenna, Kenneth W. Bruland, Jeroen E. Sonke, Hai Cheng, Mark J. Warner, Sven Ober, Rob Middag, Jessica N. Fitzsimmons, Emilie Le Roy, Yishai Weinstein, Nicholas R. Bates, Joerg Rickli, Daniel M. Sigman, Hendrik M. van Aken, Angela Milne, Cheryl M. Zurbrick, Gregory A. Cutter, Igor Semiletov, Marie Labatut, Torben Stichel, Pascale Lherminier, Gabriel Dulaquais, Jay T. Cullen, Christopher I. Measures, Mark Rosenberg, Tomoharu Minami, Mariko Hatta, Alexander L. Thomas, Gonzalo Carrasco, Karel Bakker, Clifton S. Buck, Maarten B Klunder, Willard S. Moore, Reiner Schlitzer, Tomas A. Remenyi, Susan H. Little, Eberhard Fahrbach, Charles R. McClain, Edward A. Boyle, Ursula Schauer, Linjie Zheng, Alex R. Baker, Emma Slater, Kay Thorne, Patrick Laan, Christina Schallenberg, Reiner Steinfeldt, Benjamin S. Twining, Yolanda Echegoyen-Sanz, Neil J. Wyatt, Alison M. Agather, Viena Puigcorbé, Peter Scott, Gillian Stewart, Matthew P. Humphreys, Frédéric A. C. Le Moigne, Phoebe J. Lam, Núria Casacuberta, Josh Helgoe, Edward C.V. Butler, Mark Rehkämper, Elizabeth M. Jones, Karen L. Casciotti, James W. Moffett, Tristan J. Horner, Sue Velazquez, Yuzuru Nakaguchi, Micha J.A. Rijkenberg, Antje H L Voelker, Joseph A. Resing, Lesley Salt, Eric P. Achterberg, Sven Kretschmer, Jan van Ooijen, Dominik J. Weiss, Moritz Zieringer, Carl H. Lamborg, Rick Kayser, Pierre Branellec, John M. Rolison, Sara Rauschenberg, Walter Geibert, Raja S. Ganeshram, Myriam Lambelet, Janice L. Jones, Chad R. Hammerschmidt, William J. Jenkins, Jordi Garcia-Orellana, Alessandro Tagliabue, Philip W. Boyd, Alan M. Shiller, Marcus Christl, Mark Baskaran, Mak A. Saito, Huong Thi Dieu, Morten B. Andersen, Kenji Isshiki, Taejin Kim, Christian Schlosser, Melanie K. Behrens, Albert S. Colman, Frédéric Planchon, Bettina Sohst, Andrew R. Bowie, Mark A. Brzezinski, R. Lawrence Edwards, Kristen N. Buck, Jeanette O'Sullivan, William M. Smethie, Wafa Abouchami, Valentí Rodellas, Ed C Hathorne, Robert F. Anderson, James H. Swift, Frank J. Pavia, Daniel Cossa, Lauren Kipp, Peter L. Morton, Fabien Quéroué, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Centre for Automotive Safety Research, University of Adelaide, University of California, National Oceanography Centre (NOC), Scottish Association for Marine Science (SAMS), Department of Oceanography [Cape Town], University of Cape Town, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, University of Toyama, Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Royal Netherlands Institute for Sea Research (NIOZ), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Department of Geology, Wayne State University [Detroit], The Bartlett, University College of London [London] (UCL), Institute for Environmental Research, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Department of Earth Sciences [Oxford], University of Oxford [Oxford], Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute for Research on Learning, Services communs OMP - UMS 831 (UMS 831), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UCSB), University of California-University of California, National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut Français de Recherche pour l'Exploitation de la Mer - Nantes (IFREMER Nantes), Université de Nantes (UN), University of Victoria [Canada] (UVIC), Massachusetts Institute of Technology (MIT), Universidad de Dakota del Sur, Analytical, Environmental and Geo- Chemistry, Vrije Universiteit [Brussels] (VUB), Wright State University, School of Geography, Earth and Environmental Sciences [Plymouth] (SoGEES), Plymouth University, Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Alfred Wegener Institute [Potsdam], Institute of Global Environmental Change [China] (IGEC), Xi'an Jiaotong University (Xjtu), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Department of Mathematics and Science, National Taiwan Normal University (NTNU), School of Information Technology [Kharagpur], Indian Institute of Technology Kharagpur (IIT Kharagpur), GEOMAR - Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), University of California [Davis] (UC Davis), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona [Barcelona] (UAB), Institute of Low Temperature Science, Hokkaido University, The University of Tokyo, Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania (UTAS), Joint Institute for the Study of the Atmosphere and Ocean (JISAO), University of Washington [Seattle], Institute of Geochemistry and Petrology, Détection, évaluation, gestion des risques CHROniques et éMErgents (CHROME) / Université de Nîmes (CHROME), Université de Nîmes (UNIMES), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), School of Earth and Ocean Sciences, University of Victoria, Knowledge Media Institute (KMI), The Open University [Milton Keynes] (OU), Bermuda Biological Station for Research (BBSR), Bermuda Biological Station for Research, Department of Geosciences [Princeton], Princeton University, Kyoto University [Kyoto], Géochimie des Isotopes Stables (GIS), Géosciences Environnement Toulouse (GET), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES), School of Earth and Environmental Sciences [Queens New York], Queens College [New York], City University of New York [New York] (CUNY)-City University of New York [New York] (CUNY), SOEST, University of Hawai‘i [Mānoa] (UHM), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Bigelow Laboratory for Ocean Sciences, Department of Earth Science and Technology [Imperial College London], Imperial College London, Plymouth Marine Laboratory, Rosenstiel School of Marine and Atmospheric Science (RSMAS), University of Miami [Coral Gables], Tsinghua National Laboratory for Information Science and Technology (TNList), RITE, Research Institute of Innovative Technology for the Earth, Agricultural Information Institute (AII), Chinese Academy of Agricultural Sciences (CAAS), Department of Mathematics [Shanghai], Shanghai Jiao Tong University [Shanghai], University of California [Irvine] (UCI), Institute of Environmental Science and Technology [Barcelona] (ICTA), University of California (UC), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Oxford, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Southern California (USC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Services communs OMP (UMS 831), Université Toulouse III - Paul Sabatier (UT3), Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Vrije Universiteit Brussel (VUB), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Florida International University [Miami] (FIU), Department of Earth Science and Engineering [Imperial College London], Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Universitat Autònoma de Barcelona (UAB), British Oceanographic Data Centre (BODC), Institute of Low Temperature Science [Sapporo], Hokkaido University [Sapporo, Japan], The University of Tokyo (UTokyo), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), College of Earth, Ocean, and Environment [Newark] (CEOE), University of Delaware [Newark], Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Knowledge Media Institute (KMi), Kyoto University, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Academia Sinica, University of California [Irvine] (UC Irvine), Danish Technological Institute (DTI), Scientific Committee on Oceanic Research (SCOR) from the U.S. National Science Foundation [OCE-0608600, OCE-0938349, OCE-1243377, OCE-1546580], UK Natural Environment Research Council (NERC), Ministry of Earth Science of India, Centre National de Recherche Scientifique, l'Universite Paul Sabatier de Toulouse, Observatoire Midi-Pyrenees Toulouse, Universitat Autonoma de Barcelona, Kiel Excellence Cluster The Future Ocean, Swedish Museum of Natural History, University of Tokyo, University of British Columbia, Royal Netherlands Institute for Sea Research, GEOMAR-Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute, Scientific Committee on Oceanic Research, National Science Foundation (US), Natural Environment Research Council (UK), Ministry of Earth Sciences (India), Centre National de la Recherche Scientifique (France), Université Toulouse III Paul Sabatier, Observatoire Midi-Pyrénées (France), Universidad Autónoma de Barcelona, Helmholtz Centre for Ocean Research Kiel, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (Germany), Schlitzer, Reiner [0000-0002-3740-6499], Masferrer Dodas, Elena [0000-0003-0879-1954], Chamizo, Elena [0000-0001-8266-6129], Christl, M. [0000-0002-3131-6652], Masqué, Pere [0000-0002-1789-320X], Villa-Alfageme, María [0000-0001-7157-8588], Universitat de Barcelona, Natural Environment Research Council (NERC), Leverhulme Trust, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Carrasco Rebaza, Gonzalo, Echegoyen Sanz, Yolanda, Kayser, Richard A, Isotope Research, Ocean Ecosystems, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Hassler, Christel, Schlitzer, Reiner, Masferrer Dodas, Elena, Chamizo, Elena, Christl, M., Masqué, Pere, and Villa-Alfageme, María

Subjects
Geochemistry & Geophysics, 010504 meteorology & atmospheric sciences, Isòtops, sub-01, Geotraces, MODELS, Digital data, Context (language use), 010502 geochemistry & geophysics, 01 natural sciences, IDP2017, Isotopes, Geochemistry and Petrology, Oceans, Electronic atlas, ddc:550, 0402 Geochemistry, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, NetCDF, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Trace elements, Science & Technology, Information retrieval, ACL, Geology, computer.file_format, Ocean Data View, Metadata, Data processing, GEOTRACES, 0403 Geology, Data extraction, 13. Climate action, Data quality, Physical Sciences, [SDE]Environmental Sciences, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 0406 Physical Geography and Environmental Geoscience, computer, Processament de dades, Trace elements Isotopes
Abstract

The GEOTRACES Intermediate Data Product 2017 (IDP2017) is the second publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2016. The IDP2017 includes data from the Atlantic, Pacific, Arctic, Southern and Indian oceans, with about twice the data volume of the previous IDP2014. For the first time, the IDP2017 contains data for a large suite of biogeochemical parameters as well as aerosol and rain data characterising atmospheric trace element and isotope (TEI) sources. The TEI data in the IDP2017 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at crossover stations. The IDP2017 consists of two parts: (1) a compilation of digital data for more than 450 TEIs as well as standard hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing an on-line atlas that includes more than 590 section plots and 130 animated 3D scenes. The digital data are provided in several formats, including ASCII, Excel spreadsheet, netCDF, and Ocean Data View collection. Users can download the full data packages or make their own custom selections with a new on-line data extraction service. In addition to the actual data values, the IDP2017 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering and for statistical analysis. Metadata about data originators, analytical methods and original publications related to the data are linked in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2017 as section plots and rotating 3D scenes. The basin-wide 3D scenes combine data from many cruises and provide quick overviews of large-scale tracer distributions. These 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of tracer plumes near ocean margins or along ridges. The IDP2017 is the result of a truly international effort involving 326 researchers from 25 countries. This publication provides the critical reference for unpublished data, as well as for studies that make use of a large cross-section of data from the IDP2017. This article is part of a special issue entitled: Conway GEOTRACES - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González., National Science Foundation (U.S.) (Grant OCE-0608600), National Science Foundation (U.S.) (Grant OCE0938349), National Science Foundation (U.S.) (Grant OCE-1243377), National Science Foundation (U.S.) (Grant OCE-1546580)

Published
2018
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25. Silicon cycle in Indian estuaries and its control by biogeochemical and anthropogenic processes

Author

Nittala S. Sarma, Julien Brajard, V. V. S. S. Sarma, Damien Cardinal, Irina Djouraev, D.B. Rao, G. Chiranjeevulu, K. Narasimha Murty, K.R. Mangalaa, Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Biogéochimie-Traceurs-Paléoclimat (BTP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Processus de la variabilité climatique tropicale et impacts (PARVATI), Marine Chemistry Laboratory, Andhra University, CSIR National Institute of Oceanography [India] (NIO), programme EC2CO-LEFE (project SINDIA funded by Actions CYBER and BIOHEFFECT), Erasmus Mundus Action 2 of the European Union (GATE project), Scientific Department of French Embassy in India, European Project: 294146,EC:FP7:PEOPLE,FP7-PEOPLE-2011-CIG,MUSICC(2011), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))

Subjects
Biogeochemical cycle, Monsoon, 010504 meteorology & atmospheric sciences, Weathering, Aquatic Science, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Land-to-ocean continuum, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Diatoms, geography, Amorphous silica, geography.geographical_feature_category, biology, Geology, Estuary, 15. Life on land, biology.organism_classification, 6. Clean water, Salinity, Diatom, 13. Climate action, Land use, Seawater, Eutrophication, Bay
Abstract

International audience; We study the silicon biogeochemical cycle and its associated parameters in 24 and 18 Indian estuaries during dry and wet periods respectively. We focus more specifically on dissolved Si (DSi), amorphous Si (ASi,) lithogenic Si (LSi), Particulate Organic Carbon (POC), Total Suspended Material (TSM), Dissolved Inorganic Nitrogen (DIN), salinity and fucoxanthin, a marker pigment for diatoms. Overall, we show that the estuaries have strong inter and intra variability of their biogeochemical parameters both seasonally and along salinity gradients. Based on Principal Component Analysis and clustering of categorised (upper and lower) estuaries, we discuss the four major processes controlling the Si variability of Indian estuaries: 1) lithogenic supply, 2) diatom uptake, 3) mixing of sea water and, 4) land use. The influence of lithogenic control is significantly higher during the wet period than during the dry period, due to a higher particle supply through monsoonal discharge. A significant diatom uptake is only identified in the estuaries during dry period. By taking into account the non-conservative nature of Si and by extrapolating our results, we estimate the fluxes from the Indian subcontinent of DSi, ASi, LSi to the Bay of Bengal (211 ± 32, 10 ± 4.7, 2028 ± 317 Gmol) and Arabian Sea (80 ± 15, 7 ± 1.1, 1717 ± 932 Gmol). We show the impact of land use in watersheds with higher levels of agricultural activity amplifies the supply of Si to the coastal Bay of Bengal during the wet season. In contrast, forest cover and steep slopes cause less Si supply to the Arabian Sea by restricting erosion when entering the estuary. Finally, Si:N ratios show that nitrogen is always in deficit relative to silicon for diatom growth, these high Si:N ratios likely contribute to the prevention of eutrophication in the Indian estuaries and coastal sea.

Published
2017
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27. The effects of weathering variability and anthropogenic pressures upon silicon cycling in an intertropical watershed (Tana River, Kenya)

Author

Steven Bouillon, H. Hughes, Luc André, Damien Cardinal, Department of Geology and Mineralogy, Royal Museum of Central Africa, Division of Soil and Water Management Leuven, Department of Earth and Environmental Sciences [Leuven] (EES), and Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven)-Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven)

Subjects
Hydrology, geography, geography.geographical_feature_category, Watershed, biology, Drainage basin, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Geology, Estuary, Weathering, biology.organism_classification, Salinity, Isotopic signature, Diatom, Productivity (ecology), Geochemistry and Petrology, ComputingMilieux_MISCELLANEOUS
Abstract

We present the first study of the Si isotopic composition of dry season river waters from the Tana River, Kenya. Data encompasses the entire river basin, with samples collected from headwaters to the estuary, thereby capturing a salinity gradient. In the headwaters, the isotopic signature is affected by climate, as a result of its control on soil drainage and weathering. The δ 30 Si signatures in the basin range from + 0.69‰ up to + 2.23‰. Signatures are clearly affected by dams: an increase in δ 30 Si ratios of 0.54‰ and a decrease in the dissolved Si (DSi) concentration by 41% were observed downstream of the Masinga dam, the largest of a succession of 5 hydroelectric dams. This reduction in Si load is most likely due to increased diatom productivity as the corresponding change in δ 30 Si signature is consistent with the known fractionation by these organisms. The δ 30 Si composition of waters entering the estuary is ca. + 2‰ and DSi concentrations are 349 μM. In the estuary, the DSi concentrations decrease linearly following the salinity, while the δ 30 Si ratio remains stable, indicating the absence of processes affecting the DSi pool for the studied range of salinity.

Published
2012
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28. Twilight zone organic carbon remineralization in the Polar Front Zone and Subantarctic Zone south of Tasmania

Author

Sylvie Becquevort, Frank Dehairs, Anne-Julie Cavagna, Stephanie Jacquet, Damien Cardinal, Isabelle Dumont, Earth System Sciences, Analytical and Environmental Chemistry, and Chemistry

Subjects
Polar front, Total organic carbon, chemistry.chemical_classification, Remineralisation, Mesopelagic zone, Biological pump, Carbon sequestration, mesopelagic carbon mineralization, Oceanography, Water column, chemistry, carbon transfer efficiency, Organic matter, Particulate biogenic barium, Southern Ocean, Geology
Abstract

We report on the distribution of excess, non-lithogenic particulate barium (Baxs), a proxy for twilight zone remineralization of organic matter, in the Australian sector of the Southern Ocean during the mid-austral summer 2007. This study was part of a broader investigation focusing on macro- and micronutrient availability controlling ecosystem functioning in this area. Mesopelagic particulate excess Ba (Baxs) in the twilight zone (focus was on the 100-600 m depth layer) proved to be significantly controlled by the vertical distribution of bacterial activity, with higher Baxs contents in situations where significant bacterial activity extended deeper in the water column. However, despite this covariation, the magnitude of the carbon fluxes as estimated from Baxs and bacterial activity did not match well, with carbon demand based on bacterial activity largely exceeding organic carbon remineralization estimated from Baxs. Possible reasons for this discrepancy are discussed. It appeared that the magnitude of the mesopelagic carbon remineralization flux obtained from Baxs was realistic when weighted against primary, new and export productions. Our findings corroborate earlier results indicating that mesopelagic carbon remineralization in the 100-600 m depth layer increases from the Subantarctic Zone (SAZ) toward the Polar Front, and from spring to late summer. We observed furthermore that the iron-replete Subantarctic Zone east of the Tasman Plateau had a higher mesopelagic remineralization efficiency (on average 91 +/- 20% of the carbon exported from the upper 100 m was remineralized before reaching 600 m) compared to the Fe-limited SAZ area west of the plateau and the Polar Front Zone, where mesopelagic remineralization efficiencies ranged between 21 +/- 5% and 64 +/- 24%, respectively. SAZ-East and SAZ-West sites thus differed in their efficiency of carbon sequestration into the deep ( > 600 m) water column, with SAZ-West exceeding the sequestration capacity of SAZ-East.

Published
2011
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29. Effect of seasonal biogenic silica variations on dissolved silicon fluxes and isotopic signatures in the Congo River

Author

Albert Pandi, Luc André, Damien Cardinal, Alain Laraque, H. Hughes, Christine Cocquyt, and Francis Sondag

Subjects
geography, geography.geographical_feature_category, Silicon, Water flow, Mineralogy, chemistry.chemical_element, Estuary, Fractionation, Aquatic Science, Biogenic silica, Oceanography, Water column, Flux (metallurgy), chemistry, Settling
Abstract

We report 2 yr of monthly data from the Congo River (the second largest river in the world) on dissolved silicon concentrations, biogenic silica particle concentrations, isotopic signatures of dissolved silicon, and biogenic siliceous particle counts. Diatoms predominated in the biogenic silica fraction, especially during low flow; phytoliths and sponge spicules were more abundant than diatoms only during the rainy season, when biogenic silica fluxes are low. Biological processes dominated the seasonal variations of the dissolved d30Si ratio that are superimposed on a constant abiotic d30Si value of +0.70% 6 0.05% throughout the year. The measured biogenic silica concentration is less than the amount required to explain the monthly variations of dissolved d30Si signatures. We use these signatures and a Rayleigh isotopic fractionation model to calculate that 82% 6 7% of the diatoms produced each month would be exported out of the water column, probably through settling in the Malebo Pool or further upstream. The uptake of dissolved silicon by diatoms during low water flow periods could explain the absence of the dilution effect observed for the other major elements. Annual Si export to the estuary is 1.17 3 10 10 mol yr 21 in the form of biogenic silica and 2.23 3 10 11 mol yr 21 in dissolved Si form, with a mean dissolved d 30 Si of +0.96% 6 0.27%. Phytoliths make only a minor contribution to the annual biogenic silica flux, and dissolved Si fluxes predominate over biogenic Si fluxes.

Published
2011
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30. Isotopic constraints on the Si-biogeochemical cycle of the Antarctic Zone in the Kerguelen area (KEOPS)

Author

François Fripiat, Anne-Julie Cavagna, Nicolas Savoye, Damien Cardinal, Luc André, and Frank Dehairs

Subjects
Biogeochemical cycle, Mixed layer, Stratification (water), General Chemistry, Biogenic silica, Oceanography, Atmospheric sciences, Isotope fractionation, Circumpolar deep water, Environmental Chemistry, Seawater, Photic zone, Geology, Water Science and Technology
Abstract

Estimation of the silicon (Si) mass balance in the ocean from direct measurements (Si uptake-dissolution rates …) is plagued by the strong temporal and spatial variability of the surface ocean as well as methodological artifacts. Tracers with different sensitivities toward physical and biological processes would be of great complementary use. Silicon isotopic composition is a promising proxy to improve constraints on the Si-biogeochemical cycle, since it integrates over longer timescales in comparison with direct measurements and since the isotopic balance allows to resolve the processes involved, i.e. uptake, dissolution, mixing. Si-isotopic signatures of seawater Si(OH)4 and biogenic silica (bSiO2) were investigated in late summer 2005 during the KEOPS experiment, focusing on two contrasting biogeochemical areas in the Antarctic Zone: a natural iron-fertilized area above the Kerguelen Plateau ( 1000 m water depth). For the HNLC area the Si-isotopic constraint identified Upper Circumpolar Deep Water as being the ultimate Si-source. The latter supplies summer mixed layer with 4.0 ± 0.7 mol Si m− 2 yr− 1. This supply must be equivalent to the net annual bSiO2 production and exceeds the seasonal depletion as estimated from a simple mixed layer mass balance (2.5 ± 0.2 mol Si m− 2 yr− 1). This discrepancy reveals that some 1.5 ± 0.7 mol Si m− 2 yr− 1 must be supplied to the mixed layer during the stratification period. For the fertilized plateau bloom area, a low apparent mixed layer isotopic fractionation value (∆30Si) probably reflects (1) a significant impact of bSiO2 dissolution, enriching the bSiO2 pool in heavy isotope; and/or (2) a high Si uptake over supply ratio in mixed layer at the beginning of the bloom, following an initial closed system operating mode, which, however, becomes supplied toward the end of the bloom (low Si uptake over supply ratio) with isotopically light Si(OH)4 from below when the surface Si(OH)4 pool is significantly depleted. We estimated a net integrated bSiO2 production of 10.5 ± 1.4 mol Si m− 2 yr− 1 in the AASW above the plateau, which includes a significant contribution of bSiO2 production below the euphotic layer. However, advection which could be significant for this area has not been taken into account in the latter estimation based on a 1D approach of the plateau system. Finally, combining the KEOPS Si-isotopic data with those from previous studies, we refined the average Si-isotopic fractionation factor to − 1.2 ± 0.2‰ for the Antarctic Circumpolar Current.

Published
2011
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31. Variations of δ30Si and Ge/Si with weathering and biogenic input in tropical basaltic ash soils under monoculture

Author

Sophie Opfergelt, Damien Cardinal, Laurent Bremond, C. Delvigne, Luc André, Bruno Delvaux, Royal Museum for Centrale Africa, Geology and mineralogy, section of Mineralogy and Petrography, Royal Museum for Central Africa [Tervuren] (RMCA), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), École pratique des hautes études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UR226

Subjects
2. Zero hunger, Delta, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Mineralogy, Weathering, Soil classification, 15. Life on land, Silt, 010502 geochemistry & geophysics, 01 natural sciences, 6. Clean water, [SDU]Sciences of the Universe [physics], Geochemistry and Petrology, Phytolith, Environmental chemistry, [SDE]Environmental Sciences, Soil water, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Clay minerals, Deposition (chemistry), ComputingMilieux_MISCELLANEOUS, Geology, 0105 earth and related environmental sciences
Abstract

In soils, silicon released by mineral weathering can be retrieved from soil solution through clay formation, Si adsorption onto secondary oxides and plant uptake, thereby impacting the Si-isotopic signature and Ge/Si ratio of dissolved Si (DSi) exported to rivers. Here we use these proxies to Study the contribution of biogenic Si (BSi) in a soil-plant system involving basaltic ash soils differing in weathering degree under intensive banana cropping. delta Si-30 and Ge/Si ratios were determined in bulk soils (

Published
2010
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32. Impact of soil weathering degree on silicon isotopic fractionation during adsorption onto iron oxides in basaltic ash soils, Cameroon

Author

Sophie Opfergelt, Séverine Delstanche, Luc André, Bruno Delvaux, G. de Bournonville, and Damien Cardinal

Subjects
chemistry.chemical_compound, Adsorption, Isotope fractionation, Geochemistry and Petrology, Chemistry, Environmental chemistry, Soil water, Iron oxide, Mineralogy, Soil classification, Weathering, Soil type, Clay minerals
Abstract

The sequestration of silicon in soil clay-sized iron oxides may affect the terrestrial cycle of Si. Iron oxides indeed specifically adsorb aqueous monosilicic acid (H4SiO40), thereby influencing Si concentration in soil solution. Here we study the impact of H4SiO40 adsorption on the fractionation of Si isotopes in basaltic ash soils differing in weathering degree (from two weathering sequences, Cameroon), hence in clay and Fe-oxide contents, and evaluate the potential isotopic impact on dissolved Si in surrounding Cameroon rivers. Adsorption was measured in batch experiment series designed as function of time (0-72 h) and initial concentration (ic) of Si in solution (0.61-1.18 mM) at 20 degrees C, constant pH (5.5) and ionic strength (I mM). After various soil-solution contact times, the delta Si-30 vs. NBS28 compositions were determined in selected solutions by MC-ICP-MS (Nu Plasma) in medium resolution, operating in dry plasma with Mg doping with an average precision of +/-0.15 parts per thousand (+/-2 sigma(SEM)). The quantitative adsorption of H4SiO40 by soil Fe-oxides left a solution depleted in light Si isotopes, which confirms previous study on synthetic Fe-oxides. Measured against its initial composition (delta Si-30 = +0.02 +/- 0.07 parts per thousand (+/-2 sigma(SD))), the solutions were systematically enriched in Si-30 reaching maximum delta Si-30 values ranging between +0.16 parts per thousand and +0.95 parts per thousand after 72 h contact time. The enrichment of the solution in heavy isotopes increased with increasing values of three parameters: soil weathering degree, iron oxide content, and proportion of short-range ordered Fe-oxide. The Si-isotopic signature of the solution was partly influenced by Si release, possibly through mineral dissolution and Si desorption from oxide surfaces, depending on soil type, highlighting the complex pattern of natural soils. Surrounding Cameroon rivers displayed a mean Si-isotopic signature of +1.19 parts per thousand. Our data imply that in natural environments, H4SiO40 adsorption by soil clay-sized Fe-oxides at least partly impacts the Si-isotopic signature of the soil solution exported to water streams. (C) 2009 Elsevier Ltd. All rights reserved.

Published
2009
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33. Measuring production-dissolution rates of marine biogenic silica by30Si-isotope dilution using a high-resolution sector field inductively coupled plasma mass spectrometer

Author

François Fripiat, Marc Elskens, Véronique Schoemann, Damien Cardinal, Rudolph Corvaisier, Karine Leblanc, Luc André, and Jacques Navez

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Resolution (mass spectrometry), Chemistry, 010604 marine biology & hydrobiology, Ion chromatography, Analytical chemistry, Ocean Engineering, Biogenic silica, Isotope dilution, Mass spectrometry, 01 natural sciences, 13. Climate action, 14. Life underwater, Isotope-ratio mass spectrometry, Inductively coupled plasma, Dissolution, 0105 earth and related environmental sciences
Abstract

Regional and seasonal variability of the Si dissolution:production ratios in the surface ocean have not been well assessed. Here, we propose a new method for determining these rates, using the 30 Si-isotopic dilution technique with a high-resolution sector field inductively coupled plasma mass spectrometer (HR-SF-ICP-MS). Relative analytical precision of the isotopic measurement is better than 1%, similar to that obtained by thermal ionization‐quadrupole mass spectrometry (TIMS). Accuracy and reproducibility of the isotopic measurements have been checked on artificial and natural solutions by intercomparison between two HR-SF-ICP-MS instruments and one TIMS. Measurements of real Si production and dissolution rates are illustrated for two contrasted situations with an average relative precision of 10%, including one from waters with low Si content (2 µmol L ‐1 ), which required an additional purification step by cation exchange chromatography. Si production rate from this later incubation was not significantly different from the one measured by radioactive 32 Si. The new method is faster and simpler than TIMS or isotope ratio mass spectrometry (IRMS). Its sensitivity is more than one order of magnitude better than TIMS, and it can cover the whole range of Si concentrations encountered in the ocean.

Published
2009
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34. Plant silicon isotopic signature might reflect soil weathering degree

Author

Sophie Opfergelt, Damien Cardinal, Bruno Delvaux, and Luc André

Subjects
Basalt, Isotopic signature, Pedogenesis, Adsorption, Pumice, Soil water, Environmental Chemistry, Mineralogy, Weathering, Dissolution, Geology, Earth-Surface Processes, Water Science and Technology
Abstract

Plants fractionate Si isotopes which provides a useful Si tracer in the Si soil-plant cycle. This study reports plant Si content and Si-isotopic signatures in mature banana plants grown on soils with different weathering degree, but all developed from basaltic pyroclasts in the Mungo area, Cameroon. The delta Si-30 compositions were determined in various plant parts and soil surface horizons by MC-ICP-MS in dry plasma mode with external Mg doping to a precision of +/- 0.15aEuro degrees (+/- A 2 sigma(SD)). The Si-isotopic compositions in banana plants grown on weathered clayey soils (+0.54 +/- A 0.15aEuro degrees) are heavier than on weakly developed soils rich in fresh ash and pumice (+0.02 +/- A 0.15aEuro degrees). The corresponding bulk soils display lower delta Si-30 value in weathered soil (-1.41aEuro degrees) than in poorly developed soil (-0.41aEuro degrees). We suggest that the dissolved Si source for the plant, governed firstly by dissolution of easily weatherable minerals, was isotopically enriched in heavy isotopes through clay formation over long periods. At seasonal to annual time scale, this source is influenced by a combination of following processes: Si adsorption of light isotopes onto Fe oxides, plant Si uptake and recycling in surface horizons. This would provide an isotopically heavier Si source in the more weathered soil since the Fe oxides content increases with weathering. Plant Si-isotopic signature might thus reflect the soil weathering degree. This study further suggests that in addition to weathering processes, rivers isotopic signatures likely depend on the fate of phytoliths in the soil-plant-river system.

Published
2008
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35. Desilication in Archean weathering processes traced by silicon isotopes and Ge/Si ratios

Author

Sophie Opfergelt, Axel Hofmann, Damien Cardinal, Luc André, Camille Delvigne, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))

Subjects
Archean, 010504 meteorology & atmospheric sciences, Geochemistry, Mineralogy, Silicon isotopes, Weathering, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 010502 geochemistry & geophysics, 01 natural sciences, Hydrothermal circulation, Paleosol, Precambrian, Geochemistry and Petrology, Isotopes of silicon, Dissolution, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Germanium, Geology, Early Earth, 13. Climate action, Ge/Si, Clay minerals, Paleoweathering, Pongola Supergroup
Abstract

The influence of continental weathering on oceanic seawater compositions in the Precambrian is poorly understood. Here we combine Si isotopes and Ge/Si ratios of a Mesoarchean paleosol (~ 2.95 Ga) and overlying shales as proxies for weathering processes and Si mass transfer at the early Earth's surface. Results show that, as with modern soils, neoformation of secondary clay minerals in the paleosol was associated with the fractionation of Si isotopes and Ge/Si ratios in response to chemical weathering and soil desilication. Furthermore, the loss of Fe-bearing minerals, most likely Fe-bearing smectites, produced additional controls on Si and Ge mobility, through the coupled dissolution and re-precipitation of clay minerals under reductive conditions. Opposite fractionation behaviors are observed: neoformed secondary clay minerals acted as a 28 Si and Ge sink, whereas the leaching of Fe-bearing minerals released 28 Si and Ge into soil solutions. An attempt to estimate δ 30 Si and Ge/Si signatures of released dissolved elements into soil solution provided δ 30 Si and Ge/Si signatures of about + 0.1‰ and 1.4 μmol/mol, respectively. Furthermore, shales deposited shortly after paleosol formation display δ 30 Si and Ge/Si compositions that may be explained as mixtures of the recognized paleosol components. The shale record suggests that weathering-induced desilication and leaching of Fe-bearing minerals, to a lesser extent, might have been widely effective during the Mesoarchean for the transfer of Si from the continents to the hydrosphere. Comparison of Si isotopes recorded in detrital sediments and chemical precipitates over time might thus provide a useful supplementary tool to decipher the impact of putative increases in continental weathering and desilication, relative to changes in hydrothermal and continent-derived solute inputs to ocean and ocean cooling.

Published
2016
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36. Spring phytoplankton assemblages in the Southern Ocean between Australia and Antarctica

Author

Nicolas Savoye, Damien Cardinal, Marc Elskens, Elzbieta E. Kopczynska, and Frank Dehairs

Subjects
Diatom, Oceanography, Productivity (ecology), Ecology, Phytoplankton, Chaetoceros, Autotroph, Gymnodinium, New production, Biology, General Agricultural and Biological Sciences, biology.organism_classification, Zooplankton
Abstract

Variations of phytoplankton assemblages were studied in November–December 2001, in surface waters of the Southern Ocean along a transect between the Sub-Antarctic Zone (SAZ) and the Seasonal Ice Zone (SIZ; 46.9°–64.9°S; 142°–143°E; CLIVAR-SR3 cruise). Two regions had characteristic but different phytoplankton assemblages. Nanoflagellates( 20 μm), diatoms and dinoflagellates, were more abundant in the Antarctic Zone-South (AZ-S) and the SIZ, (60.9°–64.9°S). In AZ-S and SIZ diatoms ranged between 2.7 × 105 and 1.2 × 106 cells l−1, dinoflagellates from 3.1 × 104 to 1.02 × 105 cells l−1. A diatom bloom was in progress in the AZ-S showing a peak of 1.8 × 106 cells l−1. Diatoms were dominated by Pseudo-nitzschia spp., Fragilariopsis spp., and Chaetoceros spp. Pseudo-nitzschia spp. outnumbered other diatoms in the AZ-S. Fragilaropsis spp. were most numerous in the SIZ. Dinoflagellates contained autotrophs (e.g. Prorocentrum) and heterotrophs (Gyrodinium/Gymnodinium, Protoperidinium). Diatoms and dinoflagellates contributed most to the cellular carbon: 11–25 and 17–124 μg C l−1, respectively. Small cells dominated in the northern region characterized by the lowest N-uptake and new production of the transect. Larger diatom cells were prevalent in the southern area with higher values of N-uptake and new production. Diatom and nanoflagellate cellular carbon contents were highly correlated with one another, with primary production, and productivity related parameters. They contributed up to 75% to the total autotrophic C biomass. Diatom carbon content was significantly correlated to nitrate uptake and particle export, but not to ammonium uptake, while flagellate carbon was well correlated to ammonium uptake, but not to export. Diatoms have contributed highly to particle export along the latitudinal transect, while flagellates played a minor role in the export.

Published
2007
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37. Silicon isotopes in spring Southern Ocean diatoms: Large zonal changes despite homogeneity among size fractions

Author

Thomas W. Trull, Nicolas Savoye, Damien Cardinal, Elzbieta E. Kopczynska, Jean-Louis Tison, Frank Dehairs, Luc André, and François Fripiat

Subjects
Polar front, biology, Mineralogy, General Chemistry, Biogenic silica, Oceanography, biology.organism_classification, Equilibrium fractionation, Chemical oceanography, chemistry.chemical_compound, Diatom, Isotope fractionation, chemistry, Environmental Chemistry, Seawater, Silicic acid, Geology, Water Science and Technology
Abstract

We determine Southern Ocean diatom silicon isotopic signatures and compare them with the previously published data for dissolved silicic acid from the same locations. Five stations distributed along the WOCE SR-3 transect (Australian Sector of the Southern Ocean) in different biogeochemical provinces are presented: Polar Front and Inter-Polar Front Zones (PFZ–IPFZ), Southern Antarctic Zone (AZ-S), Seasonal Ice Zone (SIZ). Total (N0.4 μm), medium-sized (20–70 μm), and large diatoms (N70 μm) were sampled at 2–4 depths in the upper 150 m. Silicon isotopic compositions of biogenic silica (diatoms) and seawater were then measured by MC-ICP-MS, in dry plasma mode using external Mg doping. Results are expressed as δ 29 Si relative to the NBS28 standard. The isotopic composition of diatoms (δ 29 SiBSi) is generally homogeneous in the mixed layer and does not exhibit a systematic isotopic fractionation linked to a size effect. δ 29 SiBSi are always lighter than the ambient dissolved silicic acid signatures (δ 29 SiDSi), reflecting the preferential uptake of light isotopes by diatoms. A trend of lighter isotopic signatures southward is observed both in diatoms and seawater samples but the δ 29 SiBSi latitudinal gradient is much steeper. A diatom signature as low as −0.26‰ in the southernmost SIZ station strongly contrasts with the +0.65‰ signature measured on PFZ diatoms. The difference between the ambient dissolved silicic acid and diatom isotopic signatures, Δ 29 Si, strongly increases southward: from 0.4 in the PFZ up to 1.08‰ in the SIZ. This points toward occurrence of mixing events in the PFZ–IPFZ with diatoms not being under equilibrium with their surrounding water and/or, possible variation of the diatom–seawater equilibrium fractionation factor, 29 e. Apart from mixing, we found that the other parameters likely responsible of such variation are temperature, dissolved Si contents and, Si specific uptake and dissolution rates although at this stage none of these could be clearly recognized as the leading cause. Thorough examination of these parameters through in vitro experiments reflecting the extreme Southern Ocean conditions is needed to determine whether the observed latitudinal variation of Δ 29 Si reflects real variable fractionation or results from nonequilibrium or different time-scales recorded between dissolved and biogenic Si isotopic signatures. Our results also call for the development of more realistic models for describing short-term isotopic composition changes due to e.g. Si consumption, export

Published
2007
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38. Barium cycling along WOCE SR3 line in the Southern Ocean

Author

Stephanie Jacquet, Marc Elskens, Frank Dehairs, Nicolas Savoye, Damien Cardinal, Analytical and Environmental Chemistry, and Chemistry

Subjects
Polar front, Alkalinity, chemistry.chemical_element, Barium, Southern Ocean, Ba-nutrients, General Chemistry, Particulates, Oceanography, Atmospheric sciences, Silicate, chemistry.chemical_compound, chemistry, Environmental Chemistry, Seawater, Dissolution, Surface water, Geology, Water Science and Technology
Abstract

Spring and summer profiles of dissolved and particulate barium (Ba) from WOCE SR3 line (145°E) in the Southern Ocean are compared and seasonal evolutions discussed. Fluxes are estimated from mass conservation equations and from differences in reservoir contents between seasons. Subtraction of barium is observed at mesopelagic depths (upper 600 m) and appears to exceed up to tenfold the combined local build-up and the deep-ocean fluxes of particulate Ba, pointing towards significant dissolution to take place in intermediate and deep waters. Although regression analyses identify silicate as the major predictor of dissolved Ba, Ba and silicate are clearly uncoupled in surface waters where Ba behaves more similar to nitrate, excluding diatoms as users of Ba. Moreover, we observe a southward decrease in the Ba vs. silicate regression slopes driven by the conditions in intermediate and deep waters and mainly marked by the location of the Polar Front. These findings corroborate existing knowledge about the predominant control by barite formation and dissolution on the oceanic Ba cycle. It suggests a decreased dissolution of barite south of the Polar Front as compared to the situation in the Polar Front Zone and the Subantarctic Zone. This is in agreement with the fact that, except for deep waters, the Antarctic Circumpolar Current water column is oversaturated with respect to barite, in contrast to the situation north of the Polar Front, where the whole water column is undersaturated [Jeandel C., B. Dupre, G. Lebaron, C. Monnin and J.F. Minster, 1996. Longitudinal distributions of dissolved barium, silica and alkalinity in the western and southern Indian Ocean. Deep-Sea Res. 1, 43 (1), 1-31; Monnin, C., C. Jeandel, T. Cattaldo and F. Dehairs, 1999. The marine barite saturation state of the world's ocean. Mar. Chem., 65, 253-261].

Published
2007
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39. An inter-laboratory comparison of Si isotope reference materials

Author

Pieter Z. Vroon, Emma Engström, Melanie J. Leng, Luc André, Ben C. Reynolds, R. Bastian Georg, Hilary J. Sloane, Sander H. J. M. van den Boorn, Magnus Land, J. Aggarwal, Sophie Opfergelt, Mark A. Brzezinski, Ilia Rodushkin, Damien Cardinal, Charlotte P. Beucher, Douglas C. Baxter, and Petrology

Subjects
Delta, Reproducibility, Isotope, Chemistry, Low resolution, Analytical chemistry, Parts-per notation, Fractionation, Mass spectrometric, Analytical Chemistry, SDG 14 - Life Below Water, Inter-laboratory, Spectroscopy
Abstract

Three Si isotope materials have been used for an inter-laboratory comparison exercise to ensure reproducibility between international laboratories investigating natural Si isotope variations using a variety of chemical preparation methods and mass spectrometric techniques. These proposed standard reference materials are (i) IRMM-018 (a SiO2 standard), (ii) Big-Batch (a fractionated SiO2 material prepared at the University of California Santa Barbara), and (iii) Diatomite (a natural diatomite sample originally deposited as marine biogenic opal). All analyses are compared with the international Si standard NBS28 (RM8546) and are in reasonable agreement (

Published
2007
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40. The geotraces intermediate data product 2014

Author

Edward Mawji, Andrew R. Bowie, François Lacan, Kenneth W. Bruland, Oliver J. Lechtenfeld, Laura F. Robinson, Martin Frank, Kuo-Fang Huang, Louise A. Zimmer, Loes J. A. Gerringa, Tobias Roeske, Jingfeng Wu, Célia Venchiarutti, Yanbin Lu, Géraldine Sarthou, Reiner Schlitzer, Tomas A. Remenyi, Yuichiro Kumamoto, Hein J W de Baar, Santiago R. Gonzalez, Mark J. Warner, Mak A. Saito, Peter N. Sedwick, Daniel C. Ohnemus, Evgenia Ryabenko, Emilie Grossteffan, Moritz Zieringer, William J. Jenkins, Gregory F. de Souza, Pinghe Cai, Martin Q. Fleisher, Johnny Stutsman, Yolanda Echegoyen-Sanz, Alessandro Tagliabue, Delphine Lannuzel, Mark Rehkämper, Abigail E. Noble, A. Radic, Lijuan Sha, Micha J. A. Rijkenberg, Mark A. Brzezinski, François Fripiat, Nicholas R. Bates, Toshitaka Gamo, Hisayuki Yoshikawa, Maija Heller, Alan M. Shiller, William M. Smethie, Joaquin E. Chaves, Elena Masferrer Dodas, Torben Stichel, Mark Rosenberg, Hai Cheng, Alicia Navidad, Patrick Laan, Peter Scott, Mark Baskaran, Stephen J.G. Galer, Frédéric Planchon, Jan van Ooijen, Huong Thi Dieu, Steven van Heuven, Feifei Deng, José Marcus Godoy, Catherine Jeandel, Xin Yuan Zheng, Frank Dehairs, Stephen R. Rintoul, Wafa Abouchami, R. Lawrence Edwards, Gideon M. Henderson, Eberhard Fahrbach, Yoshiki Sohrin, Tim M. Conway, Bronwyn Wake, Urumu Tsunogai, Evaline van Weerlee, Maeve C. Lohan, Katrin Bluhm, Robert F. Anderson, Eva Bucciarelli, Ken O. Buesseler, Marie Labatut, Peter Croot, Jana Friedrich, Christopher T. Hayes, Hendrik M. van Aken, James H. Swift, Seth G. John, Sven Kretschmer, Zichen Xue, Karel Bakker, Albert S. Colman, Pierre Branellec, Timothy C. Kenna, Benjamin S. Twining, Marie Boye, Alexander L. Thomas, Karen L. Casciotti, Jessica N. Fitzsimmons, Sabrina Speich, Jun Nishioka, Thomas M. Church, Mariko Hatta, Pere Masqué, Damien Cardinal, Charles R. McClain, Oliver Baars, Frederique le Moigne, Geoffrey J. Smith, Daniel M. Sigman, Edward A. Boyle, Ursula Schauer, Stephanie Owens, E. Malcolm S. Woodward, Maarten B Klunder, Lesley Salt, Gregory A. Cutter, Christopher I. Measures, Hajime Obata, Catherine Pradoux, Ester Garcia Solsona, James W. Moffett, Antje H L Voelker, Gabriel Dulaquais, Paul D. Quay, Saeed Roshan, Rob Middag, Johann Bown, Neil J. Wyatt, Phoebe J. Lam, Edward C.V. Butler, Michiel M Rutgers van der Loeff, Fanny Chever, Cyril Abadie, Viena Puigcorbé, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Department of Geosciences [Princeton], Princeton University, Institute for Environmental Research, Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Institute for Marine and Antarctic Studies [Horbat] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), University of California, Marine Science Institute [Santa Barbara] (MSI), University of California [Santa Barbara] (UCSB), University of California-University of California, Woods Hole Oceanographic Institution (WHOI), Australian Institute of Marine Science (AIMS), State Key Laboratory of Marine Environmental Science (MEL), Xiamen University, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), NASA Goddard Space Flight Center (GSFC), Institute of Global Environmental Change [China] (IGEC), Xi'an Jiaotong University (Xjtu), Department of Earth Sciences [Minneapolis], University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Bonn University Hospital, College of Earth, Ocean, and Environment [Newark] (CEOE), University of Delaware [Newark], University College of London [London] (UCL), Department of Earth and Ocean Sciences [Columbia], University of South Carolina [Columbia], Old Dominion University [Norfolk] (ODU), Royal Netherlands Institute for Sea Research (NIOZ), Instituto de Química, Universidade de São Paulo, British Oceanographic Data Centre (BODC), National Oceanography Centre (NOC), Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Massachusetts Institute of Technology (MIT), Universidad de Dakota del Sur, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Bermuda Institute of Ocean Sciences (BIOS), Vrije Universiteit Brussel (VUB), Department of Mathematics and Science, National Taiwan Normal University (NTNU), GEOMAR LEGOS, Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Department of Chemistry, School of Life Sciences, University of Sussex, National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona (UAB), Oceans Institute and School of Physics, The University of Western Australia (UWA), School of Natural Sciences and Centre for Marine Ecosystems Research, Edith Cowan University, EDITH COWAN UNIVERSITY-EDITH COWAN UNIVERSITY, Department of Chemistry [Dunedin], University of Otago [Dunedin, Nouvelle-Zélande], Atmosphere and Ocean Research Institute [Kashiwa-shi] (AORI), The University of Tokyo (UTokyo), Bermuda Biological Station for Research (BBSR), Bermuda Biological Station for Research, Kyoto University [Kyoto], Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), SOEST, University of Hawai‘i [Mānoa] (UHM), FM-GEOMAR, Leibniz Institute of Marine Sciences at the University of Kiel, Department of Earth Ocean and Ecological Sciences [Liverpool], University of Liverpool, Bigelow Laboratory for Ocean Sciences, Department of Biology, Tufts University [Medford], RITE, Research Institute of Innovative Technology for the Earth, Royal Museum for Central Africa [Tervuren] (RMCA), IMT Lille Douai, Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Lille Douai), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Analytical, Environmental and Geo- Chemistry, Chemistry, Analytical and Environmental Chemistry, Earth System Sciences, Analytical, Environmental & Geo-Chemistry, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), University of Tasmania (UTAS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD), University of Minnesota [Twin Cities], Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne] (LaMCoS), Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Universitat Autònoma de Barcelona [Barcelona] (UAB), The University of Tokyo, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Rheinisch-Westfälische Technische Hochschule Aachen University (RWTH), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute for Marine and Antarctic Studies [Hobart] (IMAS), University of California (UC), University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University Hospital Bonn, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), University of Sussex, Kyoto University, Laboratoire de physique des océans (LPO), Natural Environment Research Council (NERC), Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Boyle, Edward A, Fitzsimmons, Jessica Nicole, Echegoyen Sanz, Yolanda, Ocean Ecosystems, and Isotope Research

Subjects
Chemistry, Multidisciplinary, Geotraces, Digital data, trace elements, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Biology, Oceanography, ASCII, Isotopes, 0399 Other Chemical Sciences, Electronic atlas, GEOTRACES, Trace elements, 0402 Geochemistry, Environmental Chemistry, Bathymetry, 0405 Oceanography, 14. Life underwater, isotopes, Water Science and Technology, Stable isotopes, NetCDF, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Science & Technology, Information retrieval, ACL, General Chemistry, computer.file_format, Seawater samples, Ocean Data View, Metadata, Marine Sciences, Chemistry, electronic atlas, 13. Climate action, Data quality, Physical Sciences, geotraces, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, computer
Abstract

The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEIs) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data comparisons at cross-over stations. The digital data are provided in several formats, including ASCII spreadsheet, Excel spreadsheet, netCDF, and Ocean Data View collection. In addition to the actual data values the IDP2014 also contains data quality flags and 1-σ data error values where available. Quality flags and error values are useful for data filtering. Metadata about data originators, analytical methods and original publications related to the data are linked to the data in an easily accessible way. The eGEOTRACES Electronic Atlas is the visual representation of the IDP2014 data providing section plots and a new kind of animated 3D scenes. The basin-wide 3D scenes allow for viewing of data from many cruises at the same time, thereby providing quick overviews of large-scale tracer distributions. In addition, the 3D scenes provide geographical and bathymetric context that is crucial for the interpretation and assessment of observed tracer plumes, as well as for making inferences about controlling processes., National Science Foundation (U.S.) (OCE-0608600), National Science Foundation (U.S.) (OCE-0938349), National Science Foundation (U.S.) (OCE-1243377)

Published
2015
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41. Production regime and associated N cycling in the vicinity of Kerguelen Island, Southern Ocean

Author

M. Lasbleiz, Louise Oriol, Anne-Julie Cavagna, François Fripiat, L. Florez-Leiva, Damien Cardinal, Marc Elskens, Ivia Closset, Stéphane Blain, Camila Fernandez, Dominique Lefèvre, Bernard Quéguiner, L. Chirurgien, Karine Leblanc, Frank Dehairs, P. Mangion, Analytical and Environmental Chemistry and Earth System Sciences, Vrije Universiteit Brussel (VUB), Southern Cross University (SCU), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universidad de Antioquia = University of Antioquia [Medellín, Colombia], Departamento de Oceanografía [Concepción], Universidad de Concepción - University of Concepcion [Chile], Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), KEOPS 2, Analytical and Environmental Chemistry & Earth System Sciences, Vrije Universiteit [Brussel] ( VUB ), Southern Cross University, Institut méditerranéen d'océanologie ( MIO ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Toulon ( UTLN ) -Aix Marseille Université ( AMU ) -Institut de Recherche pour le Développement ( IRD ), Biogéochimie-Traceurs-Paléoclimat ( BTP ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques ( LOCEAN ), Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Universidad de Antioquia, Universidad de Concepción [Chile], Laboratoire d'Océanographie Microbienne ( LOMIC ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Centre d'océanologie de Marseille (COM), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Faculty of Sciences and Bioengineering Sciences, Earth System Sciences, Analytical, Environmental & Geo-Chemistry, Chemistry, and Analytical and Environmental Chemistry

Subjects
agrovoc:c_12834, congenital, hereditary, and neonatal diseases and abnormalities, Mixed layer, Iron fertilization, education, lcsh:Life, Kerguelen Island, lcsh:QH540-549.5, Earth Science, Bathymetry, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Earth-Surface Processes, Nitrificación, High rate, geography, Plateau, geography.geographical_feature_category, [ SDU.STU.OC ] Sciences of the Universe [physics]/Earth Sciences/Oceanography, fungi, lcsh:QE1-996.5, Primary production, nutritional and metabolic diseases, Nitrification, lcsh:Geology, Sciences de la terre et du cosmos, Antarctic Ocean, lcsh:QH501-531, Oceanography, [SDU]Sciences of the Universe [physics], Environmental science, lcsh:Ecology, Océano antártico, Cycling, agrovoc:c_468, islas Kerguelen
Abstract

Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO3− and NH4+), and nitrification rates were measured at eight stations in austral spring 2011 (October–November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m−2 d−1 and up to 0.31 d−1 respectively) compared to the HNLC reference site (12 mmol C m−2 d−1 and 0.06 d−1 respectively). Primary production was mainly sustained by nitrate uptake, with f ratios (corresponding to NO3−-uptake / (NO3−-uptake + NH4+-uptake)) lying at the upper end of the observations for the Southern Ocean (up to 0.9). We report high rates of nitrification (up to ~ 3 μmol N L−1 d−1, with ~ 90 % of them < 1 μmol N L−1 d−1) typically occurring below the euphotic zone, as classically observed in the global ocean. The specificity of the studied area is that at most of the stations, the euphotic layer was shallower than the mixed layer, implying that nitrifiers can efficiently compete with phytoplankton for the ammonium produced by remineralization at low-light intensities. Nitrate produced by nitrification in the mixed layer below the euphotic zone is easily supplied to the euphotic zone waters above, and nitrification sustained 70 ± 30 % of the nitrate uptake in the productive area above the Kerguelen Plateau. This complicates estimations of new production as potentially exportable production. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration., info:eu-repo/semantics/published

Published
2015
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42. Early spring mesopelagic carbon remineralization and transfer efficiency in the naturally iron-fertilized Kerguelen area

Author

Anne-Julie Cavagna, Luc André, Frank Dehairs, Ivia Closset, Stephanie Jacquet, Frédéric Planchon, Laurence Monin, Damien Cardinal, Urania Christaki, A. Lefevre, Centre d'océanologie de Marseille (COM), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Royal Museum for Central Africa [Tervuren] (RMCA), Biogéochimie-Traceurs-Paléoclimat (BTP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), ANR-10-BLAN-0614,KEOPS 2,Kerguelen : Comparaison plateau Ocean2(2010), European Project: 294146,EC:FP7:PEOPLE,FP7-PEOPLE-2011-CIG,MUSICC(2011), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Chemistry, Analytical and Environmental Chemistry, Earth System Sciences, and Analytical, Environmental & Geo-Chemistry

Subjects
FLUX, Mesopelagic zone, DEEP, lcsh:Life, chemistry.chemical_element, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Carbon sequestration, SEDIMENT, TWILIGHT ZONE, lcsh:QH540-549.5, Earth Science, 14. Life underwater, SOUTHERN-OCEAN, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Earth-Surface Processes, Polar front, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, Plateau, geography.geographical_feature_category, EXPORT PRODUCTION, ACL, lcsh:QE1-996.5, PHYTOPLANKTON BLOOM, Sediment, 15. Life on land, PARTICLE EXPORT, POLAR FRONT, lcsh:Geology, lcsh:QH501-531, Oceanography, chemistry, 13. Climate action, [SDU]Sciences of the Universe [physics], Meander, lcsh:Ecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bloom, Carbon, Geology, SUSPENDED BARITE
Abstract

We report on the zonal variability of mesopelagic particulate organic carbon remineralization and deep carbon transfer potential during the Kerguelen Ocean and Plateau compared Study 2 expedition (KEOPS 2; October–November 2011) in an area of the polar front supporting recurrent massive blooms from natural Fe fertilization. Mesopelagic carbon remineralization (MR) was assessed using the excess, non-lithogenic particulate barium (Baxs) inventories in mesopelagic waters and compared with bacterial production (BP), surface primary production (PP) and export production (EP). Results for this early season study are compared with the results obtained during a previous study (2005; KEOPS 1) for the same area at a later stage of the phytoplankton bloom. Our results reveal the patchiness of the seasonal advancement and of the establishment of remineralization processes between the plateau (A3) and polar front sites during KEOPS 2. For the Kerguelen plateau (A3 site) we observe a similar functioning of the mesopelagic ecosystem during both seasons (spring and summer), with low and rather stable remineralization fluxes in the mesopelagic column (150–400 m). The shallow water column (~500 m), the lateral advection, the zooplankton grazing pressure and the pulsed nature of the particulate organic carbon (POC) transfer at A3 seem to drive the extent of MR processes on the plateau. For deeper stations (>2000 m) located on the margin, inside a polar front meander, as well as in the vicinity of the polar front, east of Kerguelen, remineralization in the upper 400 m in general represents a larger part of surface carbon export. However, when considering the upper 800 m, in some cases, the entire flux of exported carbon is remineralized. In the polar front meander, where successive stations form a time series, two successive events of particle transfer were evidenced by remineralization rates: a first mesopelagic and deep transfer from a past bloom before the cruise, and a second transfer expanding at mesopelagic layers during the cruise. Regarding the deep carbon transfer efficiency, it appeared that above the plateau (A3 site) the mesopelagic remineralization was not a major barrier to the transfer of organic matter to the seafloor (close to 500 m). There, the efficiency of carbon transfer to the bottom waters (>400 m) as assessed by PP, EP and MR fluxes comparisons reached up to 87% of the carbon exported from the upper 150 m. In contrast, at the deeper locations, mesopelagic remineralization clearly limited the transfer of carbon to depths of >400 m. For sites at the margin of the plateau (station E-4W) and the polar front (station F-L), mesopelagic remineralization even exceeded upper 150 m export, resulting in a zero transfer efficiency to depths >800 m. In the polar front meander (time series), the capacity of the meander to transfer carbon to depth >800 m was highly variable (0 to 73%). The highest carbon transfer efficiencies in the meander are furthermore coupled to intense and complete deep (>800 m) remineralization, resulting again in a near-zero, deep (>2000 m) carbon sequestration efficiency there.

Published
2015
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43. Silicon Isotopic Fractionation by Banana (Musa spp.) Grown in a Continuous Nutrient Flow Device

Author

Sophie Opfergelt, Xavier Draye, Damien Cardinal, Luc André, Bruno Delvaux, and Céline Henriet

Subjects
Isotope, biology, Chemistry, fungi, Analytical chemistry, food and beverages, Soil Science, Xylem, Plant physiology, Plant Science, Fractionation, Hydroponics, Mass spectrometry, biology.organism_classification, Musa acuminata, Shoot
Abstract

The determination of the plant-induced Si-isotopic fractionation is a promising tool to better quantify their role in the continental Si cycle. Si-isotopic signatures of the different banana plant parts and Si source were measured, providing the isotopic fractionation factor between plant and source. Banana plantlets (Musa acuminata Colla, cv Grande Naine) were grown in hydroponics at variable Si supplies (0.08, 0.42, 0.83 and 1.66 mM Si). Si-isotopic compositions were determined on a multicollector plasma source mass spectrometer (MC-ICP-MS) operating in dry plasma mode. Results are expressed as delta Si-29 relative to the NBS28 standard, with an average precision of +/- 0.08 parts per thousand (+/- 2 sigma(D)). The fractionation factor (29)epsilon between bulk banana plantlets and source solution is -0.40 +/- 0.11 parts per thousand. This confirms that plants fractionate Si isotopes by depleting the source solution in Si-28. The intra-plant fractionation Delta Si-29 between roots and shoots amounts to -0.21 +/- 0.08 parts per thousand. Si-isotopi c compositions of the various plant parts indicate that heavy isotopes discrimination occurs at three levels in the plant (at the root epidermis, for xylem loading and for xylem unloading). At each step, preferential crossing of light isotopes leaves a heavier solution, and produces a lighter solution. Si-isotopic fractionation processes are further discussed in relation with Si uptake and transport in plants. These findings have important implications on the study of continental Si cycle.

Published
2006
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44. Silicon isotope fractionation between plant parts in banana: In situ vs. in vitro

Author

Sophie Opfergelt, Céline Henriet, Luc André, Bruno Delvaux, and Damien Cardinal

Subjects
Bamboo, Lamina, biology, Chemistry, Fractionation, Mass spectrometry, biology.organism_classification, Hydroponics, Petiole (botany), Geochemistry and Petrology, Phytolith, Musa acuminata, Botany, Economic Geology
Abstract

We recently showed that silicon isotopic fractionation in banana (Musa acuminata Colla, cv Grande Name) was related to phytolith production, and therefore to silica content in plant. The present study focuses on isotopic fractionation between the different plant parts. Silicon isotopic compositions were measured using a Nu plasma multicollector plasma source mass spectrometer (MC-ICP-MS) operating in dry plasma mode. The results are expressed as 6 29 Si relatively to the NBS28 standard, with an average precision and accuracy of +/- 0.08 parts per thousand (+/- 2 sigma). On mature banana (Musa acuminata Colla, cv Grande Name) from Cameroon, 629 Si ranged from +0.13 parts per thousand in the petiole to +0.49 parts per thousand in the lamina, yielding to a 0.36 parts per thousand change towards heavier isotopic composition in the upper parts of the plant. This strongly accords with results obtained on in vitro banana plantlets cultivated in hydroponics, where the delta Si-29 increase from pseudostems to lamina is 0.26 parts per thousand. These preliminary results on in situ banana show a trend of intra-plant fractionation comparable with that of in vitro hydroponics banana plantlets and with previous data obtained on bamboo. (c) 2005 Elsevier B.V. All rights reserved.

Published
2006
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45. Silicon Isotopic Fractionation in Lake Tanganyika and Its Main Tributaries

Author

Ishmaël Kimirei, Christine Cocquyt, Laurent Y. Alleman, Damien Cardinal, Jean-Pierre Descy, Pierre-Denis Plisnier, Luc André, Danny Sinyinza, Centre for Energy and Environment (CERI EE - IMT Nord Europe), Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Nord Europe), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Section of Mineralogy and Petrography, Royal Museum for Central Africa [Tervuren] (RMCA), Web Scale Trustworthy Collaborative Service Systems (COAST), Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Department of Networks, Systems and Services (LORIA - NSS), Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Centre for Energy and Environment (CERI EE), and Ecole nationale supérieure Mines-Télécom Lille Douai (IMT Lille Douai)

Subjects
010504 meteorology & atmospheric sciences, Fractionation, Aquatic Science, 010502 geochemistry & geophysics, 01 natural sciences, Nutrient, Epilimnion, Tributary, 14. Life underwater, Transect, Inductively coupled plasma mass spectrometry, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Hydrology, geography, geography.geographical_feature_category, Ecology, biology, biology.organism_classification, 6. Clean water, Diatom, [SDU]Sciences of the Universe [physics], 13. Climate action, Environmental chemistry, Surface water, Geology
Abstract

Silicon isotopic measurements in Lake Tanganyika were performed using multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in dry plasma condition. Isotopic signatures are reported for dissolved ortho-silicic acid [Si(OH)4] collected during a 1-year-long surface waters survey in the southern basin along with several of the major tributaries. Deep-water Si isotopic profiles from a north-south transect cruise conducted in July 2002 are also described. The nutrient-like shape dissolved Si profiles and the isotopic disequilibrium between surface (δ29Si = 0.87±0.08 ‰) and deep waters (0.61 ± 0.05 ‰) suggest the occurrence of biological isotopic discrimination induced by diatoms biomineralisation in a fresh water system. Short-term surface water Si isotopic and diatom biomass variations obtained during the 1-year bi-weekly monitoring (2002–2003) in the south confirms this biological effect. Five epilimnion biogenic opal samples also were analyzed. Their signature (δ29Si of 0.28 ± 0.12‰) compared to those of surrounding waters are consistent with the diatom isotopic fractionation effect measured on marine tropical diatoms. This demonstrates the species and temperature independent character of the silicon isotope fractionations by diatoms. River signatures present variable dissolved Si concentrations which were positively correlated to δ29Si values in the range of previously published world river data. Because of its fast response to climate variability, nutrient dynamics, and limnological changes, δ29Si in siliceous organisms should be very useful in studying environmental changes and particularly the recent decline of diatom Si utilization in Lake Tanganyika.

Published
2005
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46. A Reflection on Mg, Cd, Ca, Li and Si Isotopic Measurements and Related Reference Materials

Author

Albert Galy, Anton Eisenhauer, Jean Carignan, Mark Rehkämper, Damien Cardinal, Frank Wombacher, Nathalie Vigier, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Observatoire océanologique de Villefranche-sur-mer (OOVM), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010506 paleontology, calcium, cadmium, Mc icp ms, Analytical chemistry, stable isotopes, silicon, Mineralogy, Geology, magnesium, 010502 geochemistry & geophysics, 01 natural sciences, reference materials, Isotopic composition, lithium, [SDU]Sciences of the Universe [physics], 13. Climate action, Geochemistry and Petrology, MC-ICP-MS, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

This contribution aims to report the reflections we had with the scientific community during two international workshops on reference materials for stable isotopes in Davos (2002) and Nice (2003). After evaluating the isotopic homogeneity of some existing reference materials, based on either certificates, literature data or specific inter-laboratory rounds, we confirm these as primary reference materials or propose new ones relative to which stable isotope compositions should be reported. We propose DSM-3 for Mg, NIST SRM 915a for Ca, L-SVEC for Li and NBS28 for Si. Cadmium does not yet have a well identified delta zero material, although three commercial mono-elemental Cd solutions have yielded the same isotopic composition relative to one another. In order to scale the linearity of any mass spectrometer, some secondary reference materials are also proposed: Cambridge-1 solution for Mg, the “Munster-Cd” and JEPPIM Cd solutions for Cd and the “Big Batch” silicate for Si. The team from Nancy propose to prepare a mixed spike solution for Li isotopes. Well-characterised natural samples such as ocean or continental waters, diatoms, sponges, rocks and minerals are needed to validate the entire analytical procedure, particularly to take into account the effect of sample mineralisation and of chemical manipulations for elemental separation prior to analysis. Nous rapportons id les reflections de la communaute scientifique lors de deux ateliers internationaux sur les materiaux de reference et I'analyse des isotopes stables a Davos (2002) et Nice (2003). Selon I'homogeAneite isotopique de certains materiaux de reference existants, nous confirmons la validite de ces derniers ou en proposons de nouveaux, en tant que materiaux de reference de normalisation. Ceux-ci Indus: DSM-3 pour Mg, NIST SRM 915a pour Ca, L-SVEC pour Li et NBS28 pour Si. Nous n'avons pas encore defini de materiau »delta zero« pour le Cd, bien que 3 solutions commerciales mono elementaires possedent une compositon isotopique relative identique I'une par rapport a I'autre. Afin de verifier la reponse lineaire des spectrometres de masse, nous proposons aussi une serie de materiaux de controle: la solution Cambridge-1 pour Mg, la solution Munster-Cd et JEPPIM Cd pour Cd et I'echantillon Big Batch pour Si. L'equipe de Nancy propose de preparer une solution de Li a partir d'echantillons mono-isotopique. De plus, des materiaux geologiques de reference devront etre caracterises isotopiquement afin de valider la procedure analytique dans son ensemble, de la mineralisation a I'analyse, en passant par les traitements de separation chimique.

Published
2004
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47. Seasonal variations, origin, and fate of settling diatoms in the Southern Ocean tracked by silicon isotope records in deep sediment traps

Author

Andrés S. Rigual-Hernández, Irina Djouraev, SG Bray, François Thil, Damien Cardinal, Ivia Closset, Thomas W. Trull, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université catholique de Lille (UCL), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Dpt Biological Sciences, Macquarie University, Macquarie University, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, Global and Planetary Change, Biogeochemical cycle, Geotraces, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Biogenic silica, Deep sea, Substrate (marine biology), Water column, Oceanography, Settling, 13. Climate action, Sediment trap, Environmental Chemistry, 14. Life underwater, Geology, General Environmental Science
Abstract

International audience; The Southern Ocean plays a pivotal role in the control of atmospheric CO2 levels, via both physical and biological sequestration processes. The biological carbon transfer to the ocean interior is tightly coupled to the availability of other elements, especially iron as a trace-limiting nutrient and dissolved silicon as the mineral substrate that allows diatoms to dominate primary production. Importantly, variations in the silicon cycling are large but not well understood. Here we use δ30Si measurements to track seasonal flows of silica to the deep sea, as captured by sediment trap time series, for the three major zones (Antarctic, AZ; Polar Frontal, PFZ; and Sub-Antarctic, SAZ) of the open Southern Ocean. Variations in the exported flux of biogenic silica (BSi) and its δ30Si composition reveal a range of insights, including that (i) the sinking rate of BSi exceeds 200 m d−1 in summer in the AZ yet decreases to very low values in winter that allow particles to remain in the water column through to the following spring, (ii) occasional vertical mixing events affect the δ30Si composition of exported BSi in both the SAZ and AZ, and (iii) the δ30Si signature of diatoms is well conserved through the water column despite strong BSi and particulate organic carbon (POC) attenuation at depth and is closely linked to the Si consumption in surface waters. With the strong coupling observed between BSi and POC fluxes in PFZ and AZ, these data provide new constraints for application to biogeochemical models of seasonal controls on production and export.

Published
2015
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48. Biological productivity regime and associated N cycling in the vicinity of Kerguelen Island area, Southern Ocean

Author

M. Lasbleiz, François Fripiat, Louise Oriol, Ivia Closset, A.-J. Cavagna, Damien Cardinal, P. Mangion, Stéphane Blain, Dominique Lefèvre, Marc Elskens, L. Chirurgien, Frank Dehairs, Karine Leblanc, Camila Fernandez, L. Flores-Leiva, and Bernard Quéguiner

Subjects
0106 biological sciences, Oceanography, 010504 meteorology & atmospheric sciences, 13. Climate action, 010604 marine biology & hydrobiology, Environmental science, 14. Life underwater, Physical geography, Cycling, 01 natural sciences, Productivity, 0105 earth and related environmental sciences
Abstract

Although the Southern Ocean is considered a High Nutrient Low Chlorophyll area (HNLC), massive and recurrent blooms are observed over and downstream the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N-uptake (NO3− and NH4+), and nitrification rates were measured at 8 stations in austral spring 2011 (October–November) during the KEOPS2 cruise in the Kerguelen area. Iron fertilization stimulates primary production, with integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m−2 d−1 and up to 0.31 d−1, respectively) compared to the HNLC reference site (12 mmol C m−2 d−1 and 0.06 d−1, respectively). Primary production is mainly sustained by nitrate uptake, with f ratio (corresponding to NO3− uptake/(NO3− uptake + NH4+ uptake)) lying in the upper end of the observations for the Southern Ocean (up to 0.9). Unexpectedly, we report unprecedented rates of nitrification (up to ~3 mmol C m−2 d−1, with ~90% of them

Published
2014

49. Early season mesopelagic carbon remineralization and transfer efficiency in the naturally iron-fertilized Kerguelen area

Author

Frédéric Planchon, Laurence Monin, F.A. Dehairs, Ivia Closset, Shm Jacquet, A.-J. Cavagna, Luc André, and Damien Cardinal

Subjects
Remineralisation, Early season, Oceanography, Transfer efficiency, chemistry, Mesopelagic zone, chemistry.chemical_element, Carbon, Geology
Abstract

We report on the zonal variability of mesopelagic particulate organic carbon) remineralization and deep carbon transfer potential during the Kerguelen Ocean and Plateau compared Study 2 expedition (KEOPS 2; October–November 2011) in an area of the Polar Front supporting recurrent massive blooms from natural Fe fertilization. Mesopelagic carbon remineralization was assessed using the excess, non-lithogenic particulate barium (Baxs) inventories in mesopelagic waters and compared with surface primary and export productions. Results for this early season study are compared with results obtained earlier (2005; KEOPS 1) for the same area during summer. For the Kerguelen plateau (A3 site) we observe a similar functioning of the mesopelagic ecosystem during both seasons (spring and summer), with less that 30% of carbon exported from the upper 150 m being remineralized in the mesopelagic column (150–400 m). For deeper stations (> 2000 m) located on the margin, inside a Polar Front meander, as well as in the vicinity of the Polar Front, east of Kerguelen, remineralization in the upper 400 m in general represents > 30% of carbon export, but when considering the upper 800 m, in some cases, the entire flux of exported carbon is remineralized. It appears that above the plateau (A3 site) mesopelagic remineralization is not a major barrier to the transfer of organic matter to the sea-floor (close to 500 m). There the efficiency of carbon sequestration into the bottom waters (> 400 m) reached up to 87% of the carbon exported from the upper 150 m. In contrast, at the deeper locations mesopelagic remineralization clearly limits the sequestration of carbon to depths > 400 m. For sites at the margin of the plateau (station E-4W) and the Polar front (station F-L), mesopelagic remineralization even exceeds upper 150 m export, resulting in a null sequestration efficiency to depths > 800 m. In the Polar Front meander, where successive stations form a time series, the capacity of the meander to transfer carbon to depth > 800 m is highly variable (0 to 73 %). The highest carbon transfer efficiencies in the meander are furthermore coupled to intense and complete deep (> 800 m) remineralization, resulting again in a close to zero deep (> 2000 m) carbon sequestration efficiency there.

Published
2014
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50. Seasonal evolution of net and regenerated silica production around a natural Fe-fertilized area in the Southern Ocean estimated with Si isotopic approaches

Author

M. Lasbleiz, Marc Elskens, Damien Cardinal, Bernard Quéguiner, Ivia Closset, Jacques Navez, Anne-Julie Cavagna, Karine Leblanc, Earth System Sciences, Analytical and Environmental Chemistry, Chemistry, Analytical, Environmental & Geo-Chemistry, Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), CYBELE, Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Analytical and Environmental Chemistry and Earth System Sciences, Vrije Universiteit Brussel (VUB), Analytical, Environmental and Geo- Chemistry, Geology and Mineralogy - Section of Mineralogy and Petrography, Royal Museum for Central Africa [Tervuren] (RMCA), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Centre d'océanologie de Marseille (COM), and Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Biogeochemical cycle, Iron fertilization, lcsh:Life, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Biogenic silica, chemistry.chemical_compound, lcsh:QH540-549.5, Earth Science, 14. Life underwater, Silicic acid, DISSOLUTION RATES, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes, geography, Plateau, geography.geographical_feature_category, biology, lcsh:QE1-996.5, fungi, IRON FERTILIZATION, KERGUELEN PLATEAU, biology.organism_classification, lcsh:Geology, lcsh:QH501-531, Diatom, Oceanography, chemistry, [SDU]Sciences of the Universe [physics], 13. Climate action, Upwelling, lcsh:Ecology, BIOGENIC SILICA, Bloom, Geology
Abstract

A massive diatom bloom is observed each year in the surface waters of the naturally Fe-fertilized Kerguelen Plateau (Southern Ocean). We measured biogenic silica production and dissolution fluxes (ρSi and ρDiss, respectively) in the mixed layer in the vicinity of the Kerguelen Plateau during austral spring 2011 (KEOPS-2 cruise). We compare results from a high-nutrient low-chlorophyll reference station and stations with different degrees of iron enrichment and bloom conditions. Above the plateau biogenic ρSi are among the highest reported so far in the Southern Ocean (up to 47.9 mmol m−2 d−1). Although significant (10.2 mmol m−2 d−1 on average), ρDiss were generally much lower than production rates. Uptake ratios (ρSi : ρC and ρSi : ρN) confirm that diatoms strongly dominate primary production in this area. At the bloom onset, decreasing dissolution-to-production ratios (D : P) indicate that the remineralization of silica could sustain most of the low silicon uptake and that the system progressively shifts toward a silica production regime which must be mainly supported by new source of silicic acid. Moreover, by comparing results from the two KEOPS expeditions (spring 2011 and summer 2005), we suggest that there is a seasonal evolution of the processes decoupling Si and N cycles in the area. Indeed, the consumption of H4SiO4 standing stocks occurs only during the growing stage of the bloom when strong net silica production is observed, contributing to higher H4SiO4 depletion relative to NO3−. Then, the decoupling of H4SiO4 and NO3− is mainly controlled by the more efficient nitrogen recycling relative to Si. Gross Si : N uptake ratios were higher in the Fe-rich regions compared to the high-nutrient low-chlorophyll (HNLC) area, likely due to different diatom communities. This suggests that the diatom responses to natural Fe fertilization are more complex than previously thought, and that natural iron fertilization over long timescales does not necessarily decrease Si : N uptake ratios as suggested by the silicic acid leakage hypothesis. Finally, we propose the first seasonal estimate of the Si biogeochemical budget above the Kerguelen Plateau based on direct measurements. This study points out that naturally iron-fertilized areas of the Southern Ocean could sustain very high regimes of biogenic silica production, similar to those observed in highly productive upwelling systems.

Published
2014
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