Author: "Hervé Claustre" / Publisher: hal ccsd - Searchworks@Jio Institute Digital Library Search Results

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1. Wildfire aerosol deposition likely amplified a summertime Arctic phytoplankton bloom

Author: Mathieu Ardyna, Douglas S. Hamilton, Tristan Harmel, Léo Lacour, Diana N. Bernstein, Julien Laliberté, Christopher Horvat, Rémi Laxenaire, Matthew M. Mills, Gert van Dijken, Igor Polyakov, Hervé Claustre, Natalie Mahowald, Kevin Robert Arrigo, 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), Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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), Centre National de la Recherche Scientifique (CNRS), 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-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), Laboratoire de l'Atmosphère et des Cyclones (LACy), and Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Météo-France
Subjects: [SDU]Sciences of the Universe [physics], General Earth and Planetary Sciences, General Environmental Science
Abstract: Summertime wildfire activity is increasing in boreal forest and tundra ecosystems in the Northern Hemisphere. However, the impact of long range transport and deposition of wildfire aerosols on biogeochemical cycles in the Arctic Ocean is unknown. Here, we use satellite-based ocean color data, atmospheric modeling and back trajectory analysis to investigate the transport and fate of aerosols emitted from Siberian wildfires in summer 2014 and their potential impact on phytoplankton dynamics in the Arctic Ocean. We detect large phytoplankton blooms near the North Pole (up to 82°N in the eastern Eurasian Basin). Our analysis indicates that these blooms were induced by the northward plume transport and deposition of nutrient-bearing wildfire aerosols. We estimate that these highly stratified surface waters received large amounts of wildfire-derived nitrogen, which alleviated nutrient stress in the phytoplankton community and triggered an unusually large bloom event. Our findings suggest that changes in wildfire activity may strongly influence summertime productivity in the Arctic Ocean.
Published: 2022

2. The Green Edge cruise: investigating the marginal ice zone processes during late spring and early summer to understand the fate of the Arctic phytoplankton bloom

Author: Flavienne Bruyant, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Lise Artigue, Lucas Barbedo de Freitas, Guislain Bécu, Simon Bélanger, Pascaline Bourgain, Annick Bricaud, Etienne Brouard, Camille Brunet, Tonya Burgers, Danielle Caleb, Katrine Chalut, Hervé Claustre, Véronique Cornet-Barthaux, Pierre Coupel, Marine Cusa, Fanny Cusset, Laeticia Dadaglio, Marty Davelaar, Gabrièle Deslongchamps, Céline Dimier, Julie Dinasquet, Dany Dumont, Brent Else, Igor Eulaers, Joannie Ferland, Gabrielle Filteau, Marie-Hélène Forget, Jérome Fort, Louis Fortier, Martí Galí, Morgane Gallinari, Svend-Erik Garbus, Nicole Garcia, Catherine Gérikas Ribeiro, Colline Gombault, Priscilla Gourvil, Clémence Goyens, Cindy Grant, Pierre-Luc Grondin, Pascal Guillot, Sandrine Hillion, Rachel Hussherr, Fabien Joux, Hannah Joy-Warren, Gabriel Joyal, David Kieber, Augustin Lafond, José Lagunas, Patrick Lajeunesse, Catherine Lalande, Jade Larivière, Florence Le Gall, Karine Leblanc, Mathieu Leblanc, Justine Legras, Keith Lévesque, Kate-M. Lewis, Edouard Leymarie, Aude Leynaert, Thomas Linkowski, Martine Lizotte, Adriana Lopes dos Santos, Claudie Marec, Dominique Marie, Guillaume Massé, Philippe Massicotte, Atsushi Matsuoka, Lisa A. Miller, Sharif Mirshak, Nathalie Morata, Brivaela Moriceau, Philippe-Israël Morin, Simon Morisset, Anders Mosbech, Alfonso Mucci, Gabrielle Nadaï, Christian Nozais, Ingrid Obernosterer, Thimoté Paire, Christos Panagiotopoulos, Marie Parenteau, Noémie Pelletier, Marc Picheral, Bernard Quéguiner, Patrick Raimbault, Joséphine Ras, Eric Rehm, Llúcia Ribot Lacosta, Jean-François Rontani, Blanche Saint-Béat, Julie Sansoulet, Noé Sardet, Catherine Schmechtig, Antoine Sciandra, Richard Sempéré, Caroline Sévigny, Jordan Toullec, Margot Tragin, Jean-Éric Tremblay, Annie-Pier Trottier, Daniel Vaulot, Anda Vladoiu, Lei Xue, Gustavo Yunda-Guarin, Marcel Babin, 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), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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), 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), 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), Laboratoire d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche de Roscoff (FR2424), 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 Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Paris Cité (UPCité), Applied Physics Laboratory [Seattle] (APL-UW), University of Washington [Seattle], Processus et interactions de fine échelle océanique (PROTEO), 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], [SDE]Environmental Sciences, General Earth and Planetary Sciences
Abstract: The Green Edge project was designed to investigate the onset, life, and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in Arctic Ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean food chain, it is crucial to understand how changes in the Arctic environment will affect it. Green Edge was a large multidisciplinary, collaborative project bringing researchers and technicians from 28 different institutions in seven countries together, aiming at understanding these changes and their impacts on the future. The fieldwork for the Green Edge project took place over two years (2015 and 2016) and was carried out from both an ice camp and a research vessel in Baffin Bay, in the Canadian Arctic. This paper describes the sampling strategy and the dataset obtained from the research cruise, which took place aboard the Canadian Coast Guard ship (CCGS) Amundsen in late spring and early summer 2016. The sampling strategy was designed around the repetitive, perpendicular crossing of the marginal ice zone (MIZ), using not only ship-based station discrete sampling but also high-resolution measurements from autonomous platforms (Gliders, BGC-Argo floats …) and under-way monitoring systems. The dataset is available at https://doi.org/10.17882/86417 (Bruyant et al., 2022).
Published: 2022

3. The oceans’ biological carbon pumps: Framework for a research observational community approach

Author: Philip W. Boyd, Marina Lévy, Hervé Claustre, Louis Legendre, 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), University of Tasmania [Hobart, Australia] (UTAS), Processus et interactions de fine échelle océanique (PROTEO), 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), ANR-16-CE01-0014,SOBUMS,Comprendre la réponse du cycle du carbone dans l'océan austral au stress climatique(2016), and European Project: 834177,REFINE- H2020-EU.1.1
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Meteorology, Mixed layer, Science, gliders, Ocean Engineering, QH1-199.5, Aquatic Science, Oceanography, 01 natural sciences, Data assimilation, satellites, Research community, Photic zone, moorings, 14. Life underwater, Community approach, Temporal scales, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Water Science and Technology, Global and Planetary Change, 010604 marine biology & hydrobiology, General. Including nature conservation, geographical distribution, floats, biological carbon pumps, integrated observations, 13. Climate action, robotic observations, Environmental science, Satellite, ships
Abstract: A recent paradigm explains that the downward pumping of biogenic carbon in the ocean is performed by the combined action of six different biological carbon pumps (BCPs): the biological gravitational pump, the physically driven pumps (Mixed Layer Pump, Eddy Subduction Pump and Large-scale Subduction Pump), and the animal-driven pumps (diurnal and seasonal vertical migrations of zooplankton and larger animals). Here, we propose a research community approach to implement the new paradigm through the integrated study of these BCPs in the World Ocean. The framework to investigate the BCPs combines measurements from different observational platforms, i.e., oceanographic ships, satellites, moorings, and robots (gliders, floats, and robotic surface vehicles such as wavegliders and saildrones). We describe the following aspects of the proposed research framework: variables and processes to be measured in both the euphotic and twilight zones for the different BCPs; spatial and temporal scales of occurrence of the various BCPs; selection of key regions for integrated studies of the BCPs; multi-platform observational strategies; and upscaling of results from regional observations to the global ocean using deterministic models combined with data assimilation and machine learning to make the most of the wealth of unique measurements. The proposed approach has the potential not only to bring together a large multidisciplinary community of researchers, but also to usher the community toward a new era of discoveries in ocean sciences.
Published: 2021

4. Correction of Biogeochemical-Argo Radiometry for Sensor Temperature-Dependence and Drift: Protocols for a Delayed-Mode Quality Control

Author: Nathan Briggs, M. Cornec, Antoine Poteau, Quentin Jutard, Emanuele Organelli, Edouard Leymarie, Fabrizio D'Ortenzio, Catherine Schmechtig, Emmanuel Boss, Hervé Claustre, Xiaogang Xing, National Oceanography Centre [Southampton] (NOC), University of Southampton, State Key Laboratory of Satellite Ocean Environment Dynamics (SOED), State Oceanic Administration (SOA), Observatoire des sciences de l'univers Ecce Terra (ECCE TERRA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of Maine - School of Marine Sciences, 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), and Observatoire des sciences de l'univers Ecce Terra [Paris] (ECCE TERRA)
Subjects: 0106 biological sciences, Quality Control, Biogeochemical cycle, Optics and Photonics, Downwelling irradiance, 010504 meteorology & atmospheric sciences, Oceans and Seas, TP1-1185, radiometry, Radiation, 01 natural sciences, Biochemistry, Article, Analytical Chemistry, Quality (physics), BGC-Argo, Electrical and Electronic Engineering, Instrumentation, Argo, 0105 earth and related environmental sciences, Remote sensing, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010604 marine biology & hydrobiology, Chemical technology, Mode (statistics), Underwater light field, Temperature, Atomic and Molecular Physics, and Optics, Environmental science, Radiometry
Abstract: Measuring the underwater light field is a key mission of the international Biogeochemical-Argo program. Since 2012, 0–250 dbar profiles of downwelling irradiance at 380, 412 and 490 nm besides photosynthetically available radiation (PAR) have been acquired across the globe every 1 to 10 days. The resulting unprecedented amount of radiometric data has been previously quality-controlled for real-time distribution and ocean optics applications, yet some issues affecting the accuracy of measurements at depth have been identified such as changes in sensor dark responsiveness to ambient temperature, with time and according to the material used to build the instrument components. Here, we propose a quality-control procedure to solve these sensor issues to make Argo radiometry data available for delayed-mode distribution, with associated error estimation. The presented protocol requires the acquisition of ancillary radiometric measurements at the 1000 dbar parking depth and night-time profiles. A test on &gt, 10000 profiles from across the world revealed a quality-control success rate &gt, 90% for each band. The procedure shows similar performance in re-qualifying low radiometry values across diverse oceanic regions. We finally recommend, for future deployments, acquiring daily 1000 dbar measurements and one night profile per year, preferably during moonless nights and when the temperature range between the surface and 1000 dbar is the largest.
Published: 2021

5. Impact of Mesoscale Eddies on Deep Chlorophyll Maxima

Author: Rémi Laxenaire, Hervé Claustre, Sabrina Speich, M. Cornec, 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), Center for Ocean-Atmospheric Prediction Studies (COAPS), Florida State University [Tallahassee] (FSU), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, irradiance, Irradiance, Biogeosciences, 01 natural sciences, Biogeochemical Kinetics and Reaction Modeling, Oceanography: Biological and Chemical, Water column, Paleoceanography, Phytoplankton, Oceans, Research Letter, Physical and Biogeochemical Interactions, 14. Life underwater, Global Change, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biomass (ecology), Deep chlorophyll maximum, 010604 marine biology & hydrobiology, mesoscale eddies, Biogeochemistry, deep chlorophyll maximum, Eddies and Mesoscale Processes, Oceanography: General, Oceanography, Geophysics, Eddy, 13. Climate action, Anticyclone, [SDU]Sciences of the Universe [physics], Environmental science, General Earth and Planetary Sciences, BGC argo, Maxima, Cryosphere, Biogeochemical Cycles, Processes, and Modeling, Oceanography: Physical
Abstract: Deep Chlorophyll Maxima (DCM) are ubiquitous features in stratified oceanic systems. Their establishment and maintenance result from hydrographical stability favoring specific environmental conditions with respect to light and nutrient availability required for phytoplankton growth. This stability can potentially be challenged by mesoscale eddies impacting the water column's vertical structure and thus the environmental parameters that condition the subsistence of DCMs. Here, data from the global BGC‐Argo float network are collocated with mesoscale eddies to explore their impact on DCMs. We show that cyclonic eddies, by providing optimal light and nutrient conditions, increase the occurrence of DCMs characterized by Deep Biomass Maxima for phytoplankton. In contrast, DCMs in anticyclonic eddies seem to be driven by photoacclimation as they coincide with Deep Acclimation Maxima without biomass accumulation. These findings suggest that the two types of eddies potentially have different impacts on the role of DCMs in global primary production., Key Points Deep Chlorophyll Maxima are key biological features of stratified environments that escape satellite ocean‐color detectionThe impact of mesoscale eddies on DCM is assessed by matching a global BGC‐Argo database with eddies detected from satellite altimetryWhile cyclonic eddies increase biomass maxima occurrences, anticyclonic eddies favor the presence of maxima resulting from photoacclimation
Published: 2021

6. LE CENTRE D'ASSEMBLAGE THÉMATIQUE MULTI-OBSERVATIONS DU SERVICE DE SURVEILLANCE DE L'ENVIRONNEMENT MARIN COPERNICUS

Author: Bruno Buongiorno Nardelli, Eric Greiner, Stephanie Guinehut, Hélène Etienne, Hervé Claustre, Solene Jousset, Sandrine Mulet, Trang Chau, Daniele Ciani, Raphaëlle Sauzède, Nathalie Verbrugge, Frédéric Chevallier, Marion Gehlen, Collecte Localisation Satellites (CLS), Consiglio Nazionale delle Ricerche [Napoli] (CNR), 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)-Université Paris-Saclay-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Consiglio Nazionale delle la Ricerche, Istituto di Scienze Marine, Rome, Italy, 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), Shom, Ifremer, EuroGOOS AISBL, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), 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)
Subjects: Service (systems architecture), satellite, in situ, data fusion techniques, Sensor fusion, multi observations, Thematic map, 13. Climate action, [SDE]Environmental Sciences, Satellite, 14. Life underwater, CMEMS, Scale (map), Remote sensing, Copernicus
Abstract: Complementary to ocean state estimate provided by modelling/assimilation systems, a multi observations-based approach is available through the MULTI OSERVATIONS (MULTIOBS) Thematic Assembly Center (TAC) of the European Copernicus Marine Environment Monitoring Service (CMEMS).CMEMS MULTIOBS TAC proposes products based on satellite & in situ observations and state-of-the-art data fusion techniques. These products are fully qualified and documented and, are distributed through the CMEMS catalogue (http://marine.copernicus.eu/services-portfolio). They cover the global ocean for physical and biogeochemical (BGC) variables. They are available in Near-Real-Time (NRT) or as Multi-Year Products (MYP) for the past 28 to 36 years.Satellite input observations include altimetry but also sea surface temperature, sea surface salinity as well as ocean color. In situ observations of physical and BGC variables are from autonomous platform such as Argo, moorings and ship-based measurements. Data fusion techniques are based on multiple linear regression method, multidimensional optimal interpolation method or neural networks.MULTIOBS TAC provides the following products at global scale:3D temperature, salinity and geostrophic current fields, both in NRT and as MYP; 2D sea surface salinity and sea surface density fields, both in NRT and as MYP; 2D total surface and near-surface currents, both in NRT and as MYP; 3D vertical current as MYP; 2D surface carbon fields of CO2 flux (fgCO2), pCO2 and pH as MYP; Nutrient vertical distribution (including nitrate, phosphate and silicate) profiles as MYP; 3D Particulate Organic Carbon (POC) and Chlorophyll-a (Chl-a) fields as MYP. Furthermore, MULTIOBS TAC provides specific Ocean Monitoring Indicators (OMIs), based on the above products, to monitor the global ocean 3D hydrographic variability patterns (water masses) and the global ocean carbon sink.
Published: 2021

7. BGC‐Argo Floats Observe Nitrate Injection and Spring Phytoplankton Increase in the Surface Layer of Levantine Sea (Eastern Mediterranean)

Author: L. Terrats, Marine Fourrier, Alexandra Pavlidou, A. Oviedo, Thibaut Wagener, M. Puyo‐pay, M. Ribera d'Alcalà, Cathy Wimart-Rousseau, Antoine Poteau, Laurent Coppola, Dominique Lefèvre, Alexandra Gogou, Catherine Schmechtig, Pascal Conan, Stella Psarra, Franck Dumas, Hervé Claustre, Louis Marie Prieur, Vincent Taillandier, Fabrizio D'Ortenzio, Pierre-Marie Poulain, Edouard Leymarie, A.P. Karageorgis, X. Durrieu Du Madron, Dimitris Velaoras, 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), Laboratoire d'Océanographie Microbienne (LOMIC), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Service Hydrographique et Océanographique de la Marine (SHOM), Ministère de la Défense, Centre de Formation et de Recherche sur les Environnements Méditérranéens (CEFREM), Université de Perpignan Via Domitia (UPVD)-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), ANR-10-EQPX-0040,NAOS,Observations de l'océan global pour l'étude et la prévision de l'océan et du climat: préparation de la nouvelle décennie d'Argo(2010), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), and Université de Perpignan Via Domitia (UPVD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, 01 natural sciences, Eastern mediterranean, chemistry.chemical_compound, Geophysics, Oceanography, Nitrate, chemistry, 13. Climate action, Phytoplankton, Spring (hydrology), General Earth and Planetary Sciences, Environmental science, 14. Life underwater, Surface layer, Argo, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: In the eastern Mediterranean Sea, satellites have observed events of spring surface‐chlorophyll increase in the Rhodes Gyre region recurring intermittently. Few in situ biogeochemical data, however, exist to confirm their consistency, elucidate their seasonal characteristics, or discriminate among the possible drivers. During the year 2018, an array of BGC‐Argo floats was deployed in the region, collecting the first‐ever annual time series of in situ profiles of biogeochemical parameters in this area. Their observations demonstrated that nitrates, driven by mixed‐layer dynamics, were available at surface from December 2018 onwards and could have sustained phytoplankton growth. Phytoplankton accumulation at the surface was observed by satellite only in March 2019 when the mixed‐layer depth shoaled. These findings confirm that blooms occurring before the start of seasonal stratification are not easily recorded by satellite observations and reaffirm the need to consolidate the BGC‐Argo network to establish time series of the evolution of biogeochemical processes. Plain Language Summary The Levantine Sea, the easternmost area of Mediterranean Sea, is considered one of the poorest oceans on the Earth in terms of abundance of phytoplankton, the microscopic organisms that fuel the marine food web. However, historical data and satellite maps of chlorophyll (the pigment that reveals phytoplankton presence in the water) show episodic increases in the concentration of this pigment in the area near the island of Rhodes. To elucidate the characteristics of these events, a set of six robotic instruments (i.e. the BGC‐Argo floats) was deployed in the Levantine Sea in 2018. A BGC‐Argo float is an autonomous, free‐floating instrument that makes oceanic observations over the first 2,000 meters of the water column on a regular basis. This article presents an analysis of the data collected by these six robots. They provided the very first annual time series of biogeochemical observations in area, including during winter, when ship and satellite data are hard to collect. Our results reveal the increase in phytoplankton occurring before the start of seasonal stratification, increase that is not easily recorded by satellite observations and reaffirm the need to consolidate the BGC‐Argo network to establish time series of the evolution of biogeochemical processes.
Published: 2021

8. Deep Chlorophyll Maxima in the Global Ocean: Occurrences, Drivers and Characteristics

Author: Léo Lacour, Alexandre Mignot, M. Cornec, Antoine Poteau, Fabrizio D'Ortenzio, Lionel Guidi, Hervé Claustre, Catherine Schmechtig, Bernard Gentili, 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), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and Université Laval [Québec] (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, Chlorophyll a, 010504 meteorology & atmospheric sciences, irradiance, Stratification (water), 01 natural sciences, nitracline, chemistry.chemical_compound, stratification, Phytoplankton, Argo floats, BGC&#8208, Environmental Chemistry, 14. Life underwater, open ocean, 0105 earth and related environmental sciences, General Environmental Science, Global and Planetary Change, Biomass (ecology), Deep chlorophyll maximum, 010604 marine biology & hydrobiology, Pelagic zone, deep chlorophyll maximum, particle backscattering, Oceanography, chemistry, 13. Climate action, Ocean color, Chlorophyll, [SDE]Environmental Sciences, Environmental science
Abstract: International audience; Stratified oceanic systems are characterized by the presence of a so-called Deep Chlorophyll a Maximum (DCM) not detectable by ocean color satellites. A DCM can either be a phytoplankton (carbon) biomass maximum (Deep Biomass Maximum, DBM), or the consequence of photoacclimation processes (Deep photoAcclimation Maximum, DAM) resulting in the increase of chlorophyll a per phytoplankton carbon. Even though these DCM (further qualified as either DBMs or DAMs) have long been studied, no global-scale assessment has yet been undertaken and large knowledge gaps still remain in relation to the environmental drivers responsible for their formation and maintenance. In order to investigate their spatial and temporal variability in the open ocean, we use a global data set acquired by more than 500 Biogeochemical-Argo floats given that DCMs can be detected from the comparative vertical distribution of chlorophyll a concentrations and particulate backscattering coefficients. Our findings show that the seasonal dynamics of the DCMs are clearly region-dependent. High-latitude environments are characterized by a low occurrence of intense DBMs, restricted to summer. Meanwhile, oligotrophic regions host permanent DAMs, occasionally replaced by DBMs in summer, while subequatorial waters are characterized by permanent DBMs benefiting from favorable conditions in terms of both light and nutrients. Overall, the appearance and depth of DCMs are primarily driven by light attenuation in the upper layer. Our present assessment of DCM occurrence and of environmental conditions prevailing in their development lay the basis for a better understanding and quantification of their role in carbon budgets (primary production and export).
Published: 2021

9. The suspended small-particles layer in the suboxic Black Sea: a proxy for delineating the effective N2-yielding section

Author: Rafael Rasse, Hervé Claustre, Antoine Poteau, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 13. Climate action, [SDE]Environmental Sciences, 14. Life underwater
Abstract: Upper suboxic water masses confine a majority of the microbial communities that can produce up to 90 % of oceanic N2. This effective N2-yielding section encloses a suspended small-particle layer, inferred from particle backscattering (bbp) measurements. It is thus hypothesized that this layer (hereafter, the bbp-layer) is linked to N2-yielding microbial communities such as anammox and denitrifying bacteria – a hypothesis yet to be evaluated. Here, data collected by three BGC-Argo floats deployed in the Black Sea are used to investigate the origin of this bbp-layer. To this end, we evaluate how key drivers of anammox-denitrifying bacteria dynamics impact on the vertical distribution of bbp and the thickness of the bbp-layer. In conjunction with published data on N2 excess, our results suggest that the bbp-layer is at least partially composed of anammox-denitrifying bacteria for three main reasons: (1) strong correlations are recorded between bbp and nitrate; (2) the top location of the bbp-layer is driven by the ventilation of oxygen-rich subsurface waters, while its thickness is modulated by the amount of nitrate available to produce N2; (3) the maxima of both bbp and N2 excess coincide at the same isopycnals where denitrifying-anammox bacteria coexist. We thus advance that bbp and O2 can be exploited as a combined proxy to delineate the N2-yielding section of the Black Sea. This proxy can potentially contribute to refining delineation of the effective N2-yielding section of oxygen-deficient zones via data from the growing BGC-Argo float network.
Published: 2021

10. Monitoring ocean biogeochemistry with autonomous platforms

Author: Stephen C. Riser, Emmanuel Boss, Hervé Claustre, Katja Fennel, Adrienne J. Sutton, Kenneth S. Johnson, Yuntao Wang, Fei Chai, Oscar Schofield, Xiaogang Xing, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, Ecosystem health, Ocean observations, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Biogeochemistry, 01 natural sciences, Pollution, 13. Climate action, [SDE]Environmental Sciences, Environmental science, Ecosystem, Satellite, 14. Life underwater, Temporal scales, Argo, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Nature and Landscape Conservation, Earth-Surface Processes, Remote sensing
Abstract: Human activities have altered the state of the ocean, leading to warming, acidification and deoxygenation. These changes impact ocean biogeochemistry and influence ecosystem functions and ocean health. The long-term global effects of these changes are difficult to predict using current satellite sensing and traditional in situ observation techniques. Autonomous platforms equipped with biogeochemical sensors allow for the observation of marine biogeochemical processes and ecosystem dynamics, covering a wide range of spatial and temporal scales. The international Biogeochemical-Argo (BGC-Argo) project is currently building a global, multidisciplinary ocean-observing network of autonomous Argo floats equipped with an extensive range of biogeochemical sensors. Other autonomous platforms, such as gliders and surface vehicles, have also incorporated such sensors, mainly operating on regional scales and near the ocean surface. Autonomous mobile assets, along with remotely sensed data, will provide the 4D information required to improve model simulations and forecasts of ocean conditions and ecosystem health. Traditional methods for ocean observation are often inadequate for detecting large-scale biogeochemical processes. This Perspective discusses the advantages of implementing autonomous observation platforms in complementing traditional observation methods and generating global biogeochemical data sets.
Published: 2020

11. Relaxation of wind stress drives the abrupt onset of biological carbon uptake in the Kerguelen bloom: A multisensor approach

Author: Hervé Claustre, Jacqueline Boutin, Violaine Pellichero, Liliane Merlivat, Jean-Baptiste Sallée, Stéphane Blain, 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), Processus et interactions de fine échelle océanique (PROTEO), 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)), 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), Laboratoire d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LEFE‐CYBER, BNP Paribas, European Project: 264879,EC:FP7:ENV,FP7-ENV-2010,CARBOCHANGE(2011), European Project: 246777,EC:FP7:ERC,ERC-2009-AdG,REMOCEAN(2010), 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), 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 Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB)
Subjects: 0106 biological sciences, air-sea heat flux, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, onset of the phytoplankton bloom, Carbon uptake, mixing-layer depth, in situ high-resolution data, Wind stress, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 01 natural sciences, Geophysics, mixed-layer depth, 13. Climate action, Chemical physics, Abrupt onset, General Earth and Planetary Sciences, Relaxation (physics), Environmental science, 14. Life underwater, Bloom, wind stress, 0105 earth and related environmental sciences
Abstract: We deployed sensors for physical and biogeochemical measurements on one Eulerian mooring and two Lagrangian biogeochemical Argo‐floats on the Kerguelen Plateau. High temporal and vertical resolution measurements revealed an abrupt shoaling of both the mixed‐layer depth and mixing‐layer depth. The sudden stratification was concomitant with the start of significant biological activity detected by chlorophyll‐a accumulation, oxygen oversaturation and dissolved inorganic carbon drawdown. The net community production computed in the mixing‐layer during the onset period of 9 days was 119±7 mmol m‐2 d‐1. While it is generally admitted that bloom initiation is mostly driven by the onset of positive heat fluxes, our results suggest this is not a sufficient condition. Here we report that the decrease in the depth over which wind mixes the upper layer drives the initiation of the bloom. These results suggest that future atmospheric changes in Southern Ocean could impact the phenology of the blooms. Plain Language Summary The region of the Kerguelen Plateau is well known as a naturally iron fertilized region and it supports a productive marine ecosystem. In the present study, we investigate the evolution of the biogeochemical and physical conditions during the 2016 phytoplankton bloom event near the Kerguelen Plateau. We use a unique combination of moored instruments and profiling floats in order to follow the phytoplankton evolution at vertical, spatial and temporal scales and to understand the main physical drivers supporting such an abrupt bloom initiation that occurs only over a 9‐days period. The large phytoplankton bloom develops during a major shallowing event bringing in few days the mixed‐layer depth from its typical winter value to its typical summer value. This abrupt stratification of the water column is driven by a decline of the wind stress. These results have important implications considering that the wind regimes are predicted to intensify in the future in the Southern Ocean. Key Points Phytoplankton onset is detected from in‐situ high resolution multisensors data gathered by one mooring and two Biogeochemical Argo floats The bloom starts approximately two months after the net heat flux becomes positive, during an abrupt shoaling event of the mixing‐layer The bloom starts only after a decrease in the depth over which winds actively mix the upper ocean leading to a decrease of the turbulence
Published: 2020

12. Enhancement of phytoplankton biomass leeward of Tahiti as observed by Biogeochemical-Argo floats

Author: Orens Pasqueron de Fommervault, Antoine Poteau, Alexandre Mignot, Laurent Oziel, Julia Uitz, Christophe Maes, Hervé Claustre, Keitapu Maamaatuaiahutapu, V. Laurent, Raphaëlle Sauzède, Martine Rodier, Catherine Schmechtig, Elodie Martinez, Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), Alcen SEAMAR (Alcen) (ALSEAMAR), 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), Takuvik International Research Laboratory, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Géopôle du Pacifique Sud (GePaSUD), Université de la Polynésie Française (UPF), Institut de Recherche pour le Développement (IRD), 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), Météo France, Direction interrégionale de Polynésie française, France, 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), Ecosystèmes Insulaires Océaniens (UMR 241) (EIO), Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), Institut de Recherche pour le Développement (IRD)-Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de la Polynésie Française (UPF)-Institut Louis Malardé [Papeete] (ILM), 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)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Météo France, Direction interrégionale de Polynésie française, France (DIRPF), and Météo-France
Subjects: 0106 biological sciences, Chlorophyll a, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Aquatic Science, Oceanography, 01 natural sciences, Island Mass Effect, chemistry.chemical_compound, Ocean gyre, Phytoplankton, Phytoplankton biomass, 14. Life underwater, Island mass effect, Biogeochemical Argo floats, Ecology, Evolution, Behavior and Systematics, Argo, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Deep chlorophyll maximum, geography, geography.geographical_feature_category, 010604 marine biology & hydrobiology, Accumulation zone, Pelagic zone, Biogeochemical-Argo floats, chemistry, 13. Climate action, [SDE]Environmental Sciences, Environmental science, South Pacific Subtropical Gyre
Abstract: The South Pacific Subtropical Gyre (SPSG) is a vast and remote oceanic system where the variability in phytoplankton biomass and production is still largely uncertain due to the lack of in situ biogeochemical observations. The SPSG is an oligotrophic environment where the ecosystem is controlled predominantly by nutrient depletion in surface waters. However, this dynamic is altered in the vicinity of islands where increased biological activity occurs (i.e. the island mass effect, IME). This study mainly focuses on in situ observations which show evidence of an IME leeward of Tahiti (17.7 degrees S - 149.5 degrees W), French Polynesia. Physical and biogeochemical observations collected with two Biogeochemical-Argo profiling floats are used to investigate the dynamics of phytoplankton biomass. Data from the first float, drifting from April 2015 to November 2016 over > 1000 km westward of Tahiti, describe the open ocean conditions. The second float, deployed leeward of Tahiti in October 2015, stayed within 45 Ian off Tahiti for three months before it stopped communicating. In the oligotrophic central SPSG, our observations show that the deepening of the deep chlorophyll maximum (DCM) from winter to summer is light-driven and that the wintertime increase in chlorophyll a concentration in the upper layer is likely to be due to the process of photoacclimation, consistent with previous observations in oligotrophic environments. In contrast, leeward of Tahiti, the DCM widens toward the surface during late spring in association with a biological enhancement in the upper layer. Using Biogeochemical-Argo data, meteorological data from Tahiti, Hybrid Coordinate Ocean Model outputs and satellite-derived products (i.e., horizontal currents and associated fronts), the physical mechanisms involved in producing this biological enhancement leeward of Tahiti have been investigated. The IME occurs during a period of strong precipitation and in a zone of weak currents downstream of the island. We conjecture that the land drainage induces a significant supply of nitrate in the ocean upper layer (down to similar to 100 m) while a zone of weak currents in the southwestern zone behind Tahiti allows an accumulation zone to form, hence increasing phytoplankton growth up to 20 km away from the coastlines. A bio-optical-based community index suggests that the composition of the phytoplankton community differs leeward of Tahiti from that in the open ocean area, with more microphytoplankton within the IME, which is associated with an increase in the carbon export to the deeper ocean.
Published: 2020

13. Major role of particle fragmentation in regulating biological sequestration of CO 2 by the oceans

Author: Hervé Claustre, Nathan Briggs, Giorgio Dall'Olmo, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Total organic carbon, Carbon dioxide in Earth's atmosphere, Multidisciplinary, 010504 meteorology & atmospheric sciences, Mesopelagic zone, 010604 marine biology & hydrobiology, Atmospheric sciences, 01 natural sciences, Fragmentation (mass spectrometry), [SDE]Environmental Sciences, Environmental science, 14. Life underwater, Small particles, Oceanic carbon cycle, 0105 earth and related environmental sciences
Abstract: Breaking up is easy to do Sinking particles transport carbon to the seafloor, where they are buried in sediments and either provide food for benthic organisms or sequester the carbon they contain. However, only ∼30% of the maximum flux reaches depths of a kilometer. This loss cannot be fully accounted for by current measurements. Briggs et al. used data collected by robotic Biogeochemical-Argo floats to quantify total mesopelagic fragmentation and found that this process accounts for roughly half of the observed flux loss (see the Perspective by Nayak and Twardowski). Fragmentation is thus perhaps the most important process controlling the remineralization of sinking organic carbon. Science , this issue p. 791 ; see also p. 738
Published: 2020

14. A Regional Neural Network Approach to Estimate Water-Column Nutrient Concentrations and Carbonate System Variables in the Mediterranean Sea: CANYON-MED

Author: Marine Fourrier, Laurent Coppola, Hervé Claustre, Fabrizio D’Ortenzio, Raphaëlle Sauzède, Jean-Pierre Gattuso, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de la Mer de Villefranche (IMEV), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, lcsh:QH1-199.5, neural network, [SDE.MCG]Environmental Sciences/Global Changes, Reference data (financial markets), Ocean Engineering, Aquatic Science, lcsh:General. Including nature conservation, geographical distribution, Oceanography, Atmospheric sciences, 01 natural sciences, chemistry.chemical_compound, Mediterranean sea, Water column, Data assimilation, nutrients, Mediterranean Sea, carbonate system, 14. Life underwater, lcsh:Science, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Water Science and Technology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, 010604 marine biology & hydrobiology, Sampling (statistics), [SDE.ES]Environmental Sciences/Environmental and Society, Salinity, chemistry, CANYON, Carbonate, Environmental science, lcsh:Q
Abstract: A regional neural network-based method, “CANYON-MED” is developed to estimate nutrients and carbonate system variables specifically in the Mediterranean Sea over the water column from pressure, temperature, salinity, and oxygen together with geolocation and date of sampling. Six neural network ensembles were developed, one for each variable (i.e., three macronutrients: nitrates (NO3-), phosphates (PO43-) and silicates (SiOH4), and three carbonate system variables: pH on the total scale (pHT), total alkalinity (AT), and dissolved inorganic carbon or total carbon (CT), trained using a specific quality-controlled dataset of reference “bottle” data in the Mediterranean Sea. This dataset is representative of the peculiar conditions of this semi-enclosed sea, as opposed to the global ocean. For each variable, the neural networks were trained on 80% of the data chosen randomly and validated using the remaining 20%. CANYON-MED retrieved the variables with good accuracies (Root Mean Squared Error): 0.78 μmol.kg–1 for NO3-, 0.043 μmol.kg–1 for PO43- and 0.71 μmol.kg–1 for Si(OH)4, 0.014 units for pHT, 13 μmol.kg–1 for AT and 12 μmol.kg–1 for CT. A second validation on the ANTARES independent time series confirmed the method’s applicability in the Mediterranean Sea. After comparison to other existing methods to estimate nutrients and carbonate system variables, CANYON-MED stood out as the most robust, using the aforementioned inputs. The application of CANYON-MED on the Mediterranean Sea data from autonomous observing systems (integrated network of Biogeochemical-Argo floats, Eulerian moorings and ocean gliders measuring hydrological properties together with oxygen concentration) could have a wide range of applications. These include data quality control or filling gaps in time series, as well as biogeochemical data assimilation and/or the initialization and validation of regional biogeochemical models still lacking crucial reference data. Matlab and R code are available at https:// github.com/MarineFou/CANYON-MED/.
Published: 2020

15. Evaluating tropical phytoplankton phenology metrics using contemporary tools

Author: John A. Gittings, Malika Kheireddine, Dionysios E. Raitsos, Marie-Fanny Racault, Ibrahim Hoteit, Hervé Claustre, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, Satellite Imagery, Databases, Factual, lcsh:Medicine, Article, 03 medical and health sciences, 0302 clinical medicine, Water column, Phytoplankton, Ecosystem, 14. Life underwater, lcsh:Science, Indian Ocean, ComputingMilieux_MISCELLANEOUS, Trophic level, geography, Ecosystem health, Tropical Climate, Multidisciplinary, geography.geographical_feature_category, Phenology, Chlorophyll A, lcsh:R, Coral reef, 15. Life on land, Food web, 030104 developmental biology, Oceanography, 13. Climate action, Remote Sensing Technology, [SDE]Environmental Sciences, Environmental science, lcsh:Q, Seasons, 030217 neurology & neurosurgery, Environmental Monitoring
Abstract: The timing of phytoplankton growth (phenology) in tropical oceans is a crucial factor influencing the survival rates of higher trophic levels, food web structure and the functioning of coral reef ecosystems. Phytoplankton phenology is thus categorised as an ‘ecosystem indicator’, which can be utilised to assess ecosystem health in response to environmental and climatic perturbations. Ocean-colour remote sensing is currently the only technique providing global, long-term, synoptic estimates of phenology. However, due to limited available in situ datasets, studies dedicated to the validation of satellite-derived phenology metrics are sparse. The recent development of autonomous oceanographic observation platforms provides an opportunity to bridge this gap. Here, we use satellite-derived surface chlorophyll-a (Chl-a) observations, in conjunction with a Biogeochemical-Argo dataset, to assess the capability of remote sensing to estimate phytoplankton phenology metrics in the northern Red Sea – a typical tropical marine ecosystem. We find that phenology metrics derived from both contemporary platforms match with a high degree of precision (within the same 5-day period). The remotely-sensed surface signatures reflect the overall water column dynamics and successfully capture Chl-a variability related to convective mixing. Our findings offer important insights into the capability of remote sensing for monitoring food availability in tropical marine ecosystems, and support the use of satellite-derived phenology as an ecosystem indicator for marine management strategies in regions with limited data availability.
Published: 2019

16. On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array

Author: Jonathan D. Nash, Andreas Sterl, Diarmuid Ó. Conchubhair, Mathieu Belbeoch, Toste Tanhua, Lynne D. Talley, Thierry Carval, Stephanie Waterman, Yueng-Djern Lenn, Kenneth S. Johnson, Ariel Troisi, Virginie Thierry, Sarah G. Purkey, Satya Prakash, Damien Desbruyères, Giorgio Dall'Olmo, Katja Fennel, Robert Hallberg, Gregory C. Johnson, James N. Moum, Ilker Fer, Brian A. King, Gael Forget, Emily L. Shroyer, Toshio Suga, Peter R. Oke, Rik Wanninkhof, Fei Chai, Are Olsen, Emmanuel Boss, Nicolas Kolodziejczyk, Markus Jochum, Sandy J. Thomalla, N. V. Zilberman, Amy F. Waterhouse, Guillaume Maze, Alberto C. Naveira Garabato, Catherine Schmechtig, Thomas W. Trull, Andrew J. Watson, Fabrizio D'Ortenzio, Haili Wang, Kjell Arne Mork, Pedro Vélez-Belchí, Paulo H. R. Calil, Philip Sutton, Jianping Xu, Steven R. Jayne, Tetsuichi Fujiki, Howard J. Freeland, Henry C. Bittig, Cara Wilson, Hervé Claustre, Ichiro Yasuda, Annie P. S. Wong, John M. Toole, Claudia Schmid, Megan Scanderbeg, Marion Gehlen, Raffaele Ferrari, Arne Körtzinger, Toshiyuki Hibiya, Dean Roemmich, Susan Wijffels, Tamaryn Morris, Sylvie Pouliquen, Matthew H. Alford, Takeyoshi Nagai, Waldemar Walczowski, Pierre-Yves Le Traon, Molly O. Baringer, Blair J. W. Greenan, W. Brechner Owens, KiRyong Kang, Jon Turton, Fiona Carse, Shigeki Hosoda, Rama Rao E. Pattabhi, Dorothee C. E. Bakker, Stephen C. Riser, 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), Oceans and Atmosphere Flagship [Brisbane], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), 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, CSIRO Marine and Atmospheric Research (CSIRO), University of East Anglia [Norwich] (UEA), School of Marine Sciences, University of Maine, Unité de recherche Géosciences Marines (Ifremer) (GM), Oregon State University (OSU), Laboratoire de physique des océans (LPO), 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), Department of Oceanography [Halifax] (DO), Dalhousie University [Halifax], Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences [Bergen] (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), Massachusetts Institute of Technology (MIT), 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), Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics (MERMAID), 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), Cancer Genetics Branch, National Institute of Health (NIH)-National Human Genome Research Institute (NHGRI), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Biomedical Technology and Cell Therapy Research Laboratory, Montreal, Université Pierre et Marie Curie - Paris 6 (UPMC), Observatoire des sciences de l'univers Ecce Terra [Paris] (ECCE TERRA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Royal Netherlands Meteorological Institute (KNMI), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Southern Ocean Carbon and Climate Observatory, CSIR, Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML), National Oceanic and Atmospheric Administration (NOAA), Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, Evolution Paris-Seine, Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Sorbonne Paris Cité (USPC), McMaster University [Hamilton, Ontario], University of California (UC), Géosciences Marines (GM), 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)-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), 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), Observatoire des sciences de l'univers Ecce Terra [Paris] (OSU ECCE TERRA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO - UC San Diego), 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)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), and Observatoire des sciences de l'univers Ecce Terra (ECCE TERRA)
Subjects: 0106 biological sciences, lcsh:QH1-199.5, 010504 meteorology & atmospheric sciences, warming, Computer science, Data management, Matematikk og naturvitenskap: 400::Geofag: 450::Oseanografi: 452 [VDP], Sede Central IEO, Ocean Engineering, lcsh:General. Including nature conservation, geographical distribution, VDP::Oseanografi: 452, Aquatic Science, Oceanography, 01 natural sciences, salinity, Mathematics and natural scienses: 400::Geosciences: 450::Oceanography: 452 [VDP], Basic research, Multidisciplinary approach, Profiling (information science), 14. Life underwater, VDP::Oceanography: 452, lcsh:Science, Argo, 0105 earth and related environmental sciences, Water Science and Technology, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, Multi disciplinary, Oseanografi / Oceanography, business.industry, 010604 marine biology & hydrobiology, temperature, Ocean depth, floats, global, ocean, Sea surface temperature, 13. Climate action, Systems engineering, circulation, lcsh:Q, business, Oseanografi
Abstract: The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i) improve Argo’s global coverage and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems, and (iv) consider experimental sensors that might be included in the future, for example to document the spatial and temporal patterns of ocean mixing. For Core Argo and each of these enhancements, the past, present, and future progression along a path from experimental deployments to regional pilot arrays to global implementation is described. The objective is to create a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System (Legler et al., 2015). The integrated system will deliver operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities., Sí
Published: 2019

17. Hydrothermal vents trigger massive phytoplankton blooms in the Southern Ocean

Author: Mathieu Rembauville, Kevin R. Arrigo, Catherine Jeandel, Reiner Schlitzer, Francesco d'Ovidio, Sara Sergi, Jean-Baptiste Sallée, Alessandro Tagliabue, Hervé Claustre, Léo Lacour, Stéphane Blain, Mathieu Ardyna, 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), Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval [Québec] (ULaval)-Centre National de la Recherche Scientifique (CNRS), Processus et interactions de fine échelle océanique (PROTEO), 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)-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), Stanford University, Université Laval [Québec] (ULaval), 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 d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Earth Ocean and Ecological Sciences [Liverpool], University of Liverpool, 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 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), SOCLIM (Southern Ocean and climate) supported by the French research program LEFE-CYBER of INSU-CNRS, European Project: 637770,H2020,ERC-2014-STG,WAPITI(2015), European Project: 246777,EC:FP7:ERC,ERC-2009-AdG,REMOCEAN(2010), 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), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and 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)
Subjects: 0301 basic medicine, Carbon Sequestration, Biogeochemical cycle, Iron, Oceans and Seas, Science, Antarctic Regions, General Physics and Astronomy, 02 engineering and technology, Article, General Biochemistry, Genetics and Molecular Biology, Hydrothermal circulation, Carbon cycle, 03 medical and health sciences, Hydrothermal Vents, Element cycles, Phytoplankton, 14. Life underwater, lcsh:Science, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Marine biology, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Multidisciplinary, fungi, Biological pump, Biogeochemistry, General Chemistry, Carbon Dioxide, Eutrophication, 021001 nanoscience & nanotechnology, 030104 developmental biology, Oceanography, 13. Climate action, Environmental science, lcsh:Q, 0210 nano-technology, Hydrothermal vent
Abstract: Hydrothermal activity is significant in regulating the dynamics of trace elements in the ocean. Biogeochemical models suggest that hydrothermal iron might play an important role in the iron-depleted Southern Ocean by enhancing the biological pump. However, the ability of this mechanism to affect large-scale biogeochemistry and the pathways by which hydrothermal iron reach the surface layer have not been observationally constrained. Here we present the first observational evidence of upwelled hydrothermally influenced deep waters stimulating massive phytoplankton blooms in the Southern Ocean. Captured by profiling floats, two blooms were observed in the vicinity of the Antarctic Circumpolar Current, downstream of active hydrothermal vents along the Southwest Indian Ridge. These hotspots of biological activity are supported by mixing of hydrothermally sourced iron stimulated by flow-topography interactions. Such findings reveal the important role of hydrothermal vents on surface biogeochemistry, potentially fueling local hotspot sinks for atmospheric CO2 by enhancing the biological pump., Hydrothermal activity is recognized to be significant in regulating the dynamics of trace elements in the ocean. Here the authors report the first observational evidence of upwelled hydrothermally influenced deep waters stimulating massive phytoplankton blooms in the Southern Ocean.
Published: 2019

18. Beyond Chlorophyll Fluorescence: The Time is Right to Expand Biological Measurements in Ocean Observing Programs

Author: Marcela Cornejo, Julia Uitz, Heidi M. Sosik, Patricia Miloslavich, Bernadette M. Sloyan, Katja Fennel, Johannes Karstensen, Sandy J. Thomalla, Hervé Claustre, Silvia G. Acinas, Anthony J. Richardson, Rik Wanninkhof, Sonia D. Batten, Hidekatsu Yamazaki, Frank E. Muller-Karger, Emmanuel Boss, Ilana Berman-Frank, Gérald Grégori, Anya M. Waite, University of Maine, Climate Sciences Department [Bremerhaven], Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), University of South Florida [Tampa] (USF), Tokyo University of Science [Tokyo], National Oceanic and Atmospheric Administration (NOAA), 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), Southern Ocean Carbon and Climate Observatory, CSIR, Woods Hole Oceanographic Institution (WHOI), CSIRO, Oceans and Atmosphere, Hobart, TAS, Australia, CSIRO Oceans and Atmosphere Flagship, Brisbane, QLD, Australia, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), 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), Department of Oceanography [Halifax] (DO), Dalhousie University [Halifax], Universidad de Concepción - University of Concepcion [Chile], University of Haifa [Haifa], SAPHOS, Nanaimo, BC, Canada, Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Universidad de Concepción [Chile]
Subjects: 0106 biological sciences, Ocean, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Measurements, Sampling (statistics), Observation, Aquatic Science, Oceanography, Plankton, 01 natural sciences, Data science, Earth system science, ComputingMethodologies_PATTERNRECOGNITION, 13. Climate action, Multidisciplinary approach, [SDE]Environmental Sciences, 14. Life underwater, 0105 earth and related environmental sciences, Water Science and Technology
Abstract: Virtual issue The Remote Sensing of Oceans, Estuaries, and Lakes.-- 2 pages, A new Scientific Committee for Ocean Research (SCOR, http://www.scor‐int.org/) working group has been formed, entitled SCOR WG‐154 “Integration of Plankton‐Observing Sensor Systems to Existing Global Sampling Programs (P‐OBS, http://www.scor‐int.org/SCOR_WGs_WG154.htm.).” The working group (P‐OBS WG) is reviewing biological sensing technologies and measurements that are ready for integration into existing regional and global ocean observing programs. Multidisciplinary sets of measurements, whose choice is guided by research and societal benefit goals, will transform our understanding of ocean biology and its impacts on Earth systems, The idea to establish the P‐OBS SCOR working group was conceived following discussions at the Global Ocean Observing System (GOOS) workshop on implementation of Multi‐Disciplinary Sustained Ocean Observations (IMSOO, http://www.goosocean.org/index.php?option=com_oe&task=viewEventRecord&eventID=1825), funded by NSF, NASA, and NOAA
Published: 2018

19. Toward deeper development of Biogeochemical-Argo floats

Author: Fei Chai, Emmanuel Boss, Xiao Gang Xing, Hervé Claustre, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, Biogeochemical cycle, particle, 010504 meteorology & atmospheric sciences, ph, Argo project, Oceanography, 01 natural sciences, lcsh:Oceanography, marine biogeochemistry, nitrate, Phytoplankton, lcsh:GC1-1581, 14. Life underwater, lcsh:Environmental sciences, Argo, 0105 earth and related environmental sciences, lcsh:GE1-350, Profiling (computer programming), 010604 marine biology & hydrobiology, Biogeochemical-Argo, dissolved oxygen, [SDE]Environmental Sciences, phytoplankton, Environmental science
Abstract: International audience; Toward deeper development of Biogeochemical-Argo floats XING Xiao-Gang a , CLAUSTRE Hervé b , BOSS Emmanuel c and CHAI Fei a,c a second institute of oceanography, state oceanic Administration, hangzhou, china
Published: 2018

20. Biogeochemical-Argo float oservations of seasonal dynamics and disturbance of phytoplankton biomass in a South Pacific island wake

Author: Sauzède, R., Martinez, E., Pasqueron Fommervault, O., Antoine Poteau, Mignot, A., Maes, C., Keitapu Maamaatuaiahutapu, Rodier, M., Hervé Claustre, Schmechtig, C., Laurent, V., Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), DYNBIO LEGOS, 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)-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)-Centre National de la Recherche Scientifique (CNRS), Géopôle du Pacifique Sud (GePaSUD), Université de la Polynésie Française (UPF), Territoires, Environnement, Télédétection et Information Spatiale (UMR TETIS), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad), 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), 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)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-AgroParisTech-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), 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)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Electronique et des Technologies de l'Information (CEA-LETI), Université Grenoble Alpes (UGA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), 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)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)
Subjects: Biogeochemical-Argo float, Seasonal disturbance, Phytoplankton biomass, Seasonal dynamics, South Pacific island wake, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience
Published: 2018

21. Unexpected winter phytoplankton blooms in the North Atlantic subpolar gyre

Author: Daniele Iudicone, Mathieu Ardyna, Hervé Claustre, M. Ribera d'Alcalà, Antoine Poteau, Louis Marie Prieur, K. F. Stec, Léo Lacour, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Stazione Zoologica Anton Dohrn (SZN), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - 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)-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), 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]), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Villefranche-sur-mer (OOVM), 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)-Centre National de la Recherche Scientifique (CNRS), Centre Régional de Recherche et d’Expérimentation en Agriculture Biologique de Midi-Pyrénées (CREAB MP), Université du Littoral Côte d'Opale-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and 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)
Subjects: 0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biogeochemical cycle, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, biology, Mixed layer, 010604 marine biology & hydrobiology, Spring bloom, biology.organism_classification, 01 natural sciences, Oceanography, Diatom, Eddy, 13. Climate action, Ocean gyre, Nanophytoplankton, Phytoplankton, General Earth and Planetary Sciences, Environmental science, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: In mid- and high-latitude oceans, winter surface cooling and strong winds drive turbulent mixing that carries phytoplankton to depths of several hundred metres, well below the sunlit layer. This downward mixing, in combination with low solar radiation, drastically limits phytoplankton growth during the winter, especially that of the diatoms and other species that are involved in seeding the spring bloom. Here we present observational evidence for widespread winter phytoplankton blooms in a large part of the North Atlantic subpolar gyre from autonomous profiling floats equipped with biogeochemical sensors. These blooms were triggered by intermittent restratification of the mixed layer when mixed-layer eddies led to a horizontal transport of lighter water over denser layers. Combining a bio-optical index with complementary chemotaxonomic and modelling approaches, we show that these restratification events increase phytoplankton residence time in the sunlight zone, resulting in greater light interception and the emergence of winter blooms. Restratification also caused a phytoplankton community shift from pico- and nanophytoplankton to phototrophic diatoms. We conclude that transient winter blooms can maintain active diatom populations throughout the winter months, directly seeding the spring bloom and potentially making a significant contribution to over-winter carbon export. Transient winter restratification events can promote phytoplankton blooms in the North Atlantic subpolar gyre, according to float data. Typical winter conditions feature a deep mixed layer that limits phytoplankton activity.
Published: 2017

22. Water intrusions and particle signatures in the Black Sea: a Biogeochemical-Argo float investigation

Author: Chaterine Schmechtig, Sebastian Grayek, Hervé Claustre, Emil V. Stanev, Antoine Poteau, 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), 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: 0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Backscatter, 010604 marine biology & hydrobiology, Mineralogy, Inflow, Oceanography, 01 natural sciences, Anoxic waters, Wavelength, 13. Climate action, Particle-size distribution, 14. Life underwater, Particle size, Argo, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Continuous observations during 3 years with a vertical resolution of 1 dbar from two Bio-Argo floats in the Black Sea that were equipped with oxygen optodes, chlorophyll fluorometers, and backscattering sensors are analyzed. The particle backscattering coefficient, b bp provides a proxy for the concentration of suspended particles. The observations clearly identify thermal and b bp intrusions down to ~700–800 m in the Bosporus inflow area. In this area, b bp is more than five times larger than elsewhere, which could indicate bacterial abundance and possible biological involvement in the precipitation of Mn-containing particles. The b bp anomalies become much shallower than the temperature anomalies with increasing distance to the east of the strait. Their maxima are located between the onset of the suboxic zone and the upper part of the anoxic layer. Unlike well-known intrusions that are caused by inflow, open ocean intrusions are shallower and often characterized by multiple layers of backscatter maxima with thicknesses of only 15–20 m. The ratio between backscattering coefficients measured at two wavelengths, which gives a proxy for particle size, shows that the relative amount of larger size particles in the anoxic layer increases with depth. The particle concentrations and their size distribution display different vertical variability, which indicates the complex transformation of biological matter. The lower concentration of particles and lower chlorophyll-a during the extremely warm 2016 reveals an overall positive correlation between the two properties. The trends in the particle backscattering coefficient in the suboxic zone during 2013–2016 could indirectly reveal a biogeochemical response to temperature changes.
Published: 2017

23. Assessing Pigment-Based Phytoplankton Community Distributions in the Red Sea

Author: Malika Kheireddine, Mustapha Ouhssain, Bernard Gentili, Julia Uitz, Hervé Claustre, Burton H. Jones, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Cyanobacteria, lcsh:QH1-199.5, 010504 meteorology & atmospheric sciences, prymnesiophytes, pigments, Ocean Engineering, lcsh:General. Including nature conservation, geographical distribution, Aquatic Science, Biology, Oceanography, Spatial distribution, cyanobacteria, 01 natural sciences, diatoms, Carbon cycle, Pigment, Water column, red sea, Nanophytoplankton, Phytoplankton, Marine Science, 14. Life underwater, lcsh:Science, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Water Science and Technology, Global and Planetary Change, 010604 marine biology & hydrobiology, phytoplankton distribution, biology.organism_classification, Synechococcus, 13. Climate action, visual_art, [SDE]Environmental Sciences, visual_art.visual_art_medium, lcsh:Q, primary production
Abstract: Pigment-based phytoplankton community composition and primary production were investigated for the first time in the Red Sea in February-April 2015 to demonstrate how the strong south to north environmental gradients determine phytoplankton community structure in Red Sea offshore regions (along the central axis). Taxonomic pigments were used as size group markers of pico, nano-, and microphytoplankton. Phytoplankton primary production rates associated with the three phytoplankton groups (pico-, nano-, and microphytoplankton) were estimated using a bio-optical model. Pico- (Synechococcus and Prochlorococcus sp.) and Nanophytoplankton (Prymnesiophytes and Pelagophytes) were the dominant size groups and contributed to 49 and 38%, respectively, of the phytoplankton biomass. Microphytoplankton (diatoms) contributed to 13% of the phytoplankton biomass within the productive layer (1.5 Zeu). Sub-basin and mesoscale structures (cyclonic eddy and mixing) were exceptions to this general trend. In the southern Red Sea, diatoms and picophytoplankton contributed to 27 and 31% of the phytoplankton biomass, respectively. This result induced higher primary production rates (430 ± 50 mgC m−2 d−1) in this region (opposed to CRS and NRS). The cyclonic eddy contained the highest microphytoplankton proportion (45% of TChla) and the lowest picophytoplankton contribution (17% of TChla) while adjacent areas were dominated by pico- and nano-phytoplankton. We estimated that the cyclonic eddy is an area of enhanced primary production, which is up to twice those of the central part of the basin. During the mixing of the water column in the extreme north of the basin, we observed the highest TChla integrated (40 mg m−2) and total primary production rate (640 mgC m−2 d−1) associated with the highest nanophytoplankton contribution (57% of TChla). Microphytoplankton were a major contributor to total primary production (54%) in the cyclonic eddy. The contribution of picophytoplankton (Synechococcus and Prochlorococcus sp.) reached maximum values (49%) in the central Red Sea. Nanophytoplankton seem to provide a ubiquitous substantial contribution (30–56%). Our results contribute to providing new insights on the spatial distribution and structure of phytoplankton groups. An understanding and quantification of the carbon cycle in the Red Sea was made based on estimates of primary production associated with pico-, nano-, and microphytoplankton.
Published: 2017

24. Physical and biogeochemical controls of the phytoplankton blooms in North-Western Mediterranean Sea: A multiplatform approach over a complete annual cycle (2012-2013 DEWEX experiment)

Author: Hervé Claustre, Anthony Bosse, Nicolas Mayot, Fabrizio D'Ortenzio, Pascal Conan, Pierre Testor, Vincent Taillandier, Orens Pasqueron de Fommervault, Louis Marie Prieur, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Variabilité de l'Océan et de la Glace de mer (VOG), 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), Bio‐Argo project funded by CNES‐TOSCA, LEFE Cyber, European Project: 246777,EC:FP7:ERC,ERC-2009-AdG,REMOCEAN(2010), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-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: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Oceanography, 01 natural sciences, Algal bloom, Geochemistry and Petrology, Phytoplankton, Earth and Planetary Sciences (miscellaneous), Photic zone, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Deep chlorophyll maximum, multiplatform approach, 010604 marine biology & hydrobiology, phytoplankton blooms, Spring bloom, Annual cycle, deep convection, Geophysics, 13. Climate action, Space and Planetary Science, Ocean color, Environmental science, Bloom
Abstract: International audience; The North Western Mediterranean Sea exhibits recurrent and significant autumnal and spring phytoplankton blooms. The existence of these two blooms coincides with typical temperate dynamics. To determine the potential control of physical and biogeochemical factors on these phytoplankton blooms, data from a multiplatform approach (combining ships, Argo and BGC‐Argo floats, and bio‐optical gliders) were analyzed in association with satellite observations in 2012–2013. The satellite framework allowed a simultaneous analysis over the whole annual cycle of in situ observations of mixed layer depth, photosynthetical available radiation, particle backscattering, nutrients (nitrate and silicate), and chlorophyll‐a concentrations. During the year 2012–2013, satellite ocean color observations, confirmed by in situ data, have revealed the existence of two areas (or bioregions) with comparable autumnal blooms but contrasting spring blooms. In both bioregions, the ratio of the euphotic zone (defined as the isolume 0.415 mol photons m−2 d−1, Z0.415) and the MLD identified the initiation of the autumnal bloom, as well as the maximal annual increase in [Chl‐a] in spring. In fact, the autumnal phytoplankton bloom might be initiated by mixing of the summer shallowing deep chlorophyll maximum, while the spring restratification (when Z0.415/MLD ratio became >1) might induce surface phytoplankton production that largely overcomes the losses. Finally, winter deep convection events that took place in one of the bioregions induced higher net accumulation rate of phytoplankton in spring associated with a diatom‐dominated phytoplankton community principally. We suggest that very deep winter MLD lead to an increase in surface silicates availability, which favored the development of diatoms.
Published: 2017

25. Bringing Biogeochemistry into the Argo Age

Author: Kenneth S. Johnson, Hervé Claustre, 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), 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: 0106 biological sciences, Oceanography, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Climatology, [SDE]Environmental Sciences, General Earth and Planetary Sciences, Biogeochemistry, Environmental science, 01 natural sciences, Argo, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Plans are underway to integrate and augment a collection of regional programs to form a global biogeochemical monitoring network.
Published: 2016

26. A Novel Near-Real-Time Quality-Control Procedure for Radiometric Profiles Measured by Bio-Argo Floats: Protocols and Performances

Author: Annick Bricaud, Catherine Schmechtig, Hervé Claustre, Antoine Poteau, Louis Marie Prieur, Xiaogang Xing, Fabrizio D'Ortenzio, Giorgio Dall'Olmo, Emanuele Organelli, Vincenzo Vellucci, Plymouth Marine Laboratory (PML), 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Observatoire des sciences de l'univers Ecce Terra [Paris] (OSU ECCE TERRA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Oregon State University (OSU), Plymouth Marine Laboratory, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Observatoire des sciences de l'univers Ecce Terra [Paris] (ECCE TERRA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Observatoire des sciences de l'univers Ecce Terra (ECCE TERRA)
Subjects: 0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, 010604 marine biology & hydrobiology, Irradiance, Ocean Engineering, radiometry, Noon, 01 natural sciences, Signal, quality-control, Quality (physics), Almost Every Day, Environmental science, Radiometric dating, 14. Life underwater, argo, Argo, 0105 earth and related environmental sciences, Remote sensing, Communication channel
Abstract: An array of Bio-Argo floats equipped with radiometric sensors has been recently deployed in various open ocean areas representative of the diversity of trophic and bio-optical conditions prevailing in the so-called case 1 waters. Around solar noon and almost every day, each float acquires 0–250-m vertical profiles of photosynthetically available radiation and downward irradiance at three wavelengths (380, 412, and 490 nm). Up until now, more than 6500 profiles for each radiometric channel have been acquired. As these radiometric data are collected out of an operator’s control and regardless of meteorological conditions, specific and automatic data processing protocols have to be developed. This paper presents a data quality-control procedure aimed at verifying profile shapes and providing near-real-time data distribution. This procedure is specifically developed to 1) identify main issues of measurements (i.e., dark signal, atmospheric clouds, spikes, and wave-focusing occurrences) and 2) validate the final data with a hierarchy of tests to ensure a scientific utilization. The procedure, adapted to each of the four radiometric channels, is designed to flag each profile in a way compliant with the data management procedure used by the Argo program. Main perturbations in the light field are identified by the new protocols with good performances over the whole dataset. This highlights its potential applicability at the global scale. Finally, the comparison with modeled surface irradiances allows for assessing the accuracy of quality-controlled measured irradiance values and identifying any possible evolution over the float lifetime due to biofouling and instrumental drift.
Published: 2016

27. A compilation of global bio-optical in situ data for ocean-colour satellite applications

Author: Richard Crout, Vittorio E. Brando, Timothy J Smyth, Mati Kahru, Hubert Loisel, Malcolm Taberner, Ray Barlow, Robert Arnone, Simon Bélanger, Giuseppe Zibordi, David Antoine, Hervé Claustre, Alex J. Poulton, Robert Frouin, Stuart W. Gibb, Michael Ondrusek, Michael S. Twardowski, Tiffany Moisan, Steve Groom, Heidi M. Sosik, Francisco P. Chavez, Stanford B. Hooker, Holger Klein, Richard W. Gould, Michel Repecaud, William M. Balch, Vanda Brotas, Kenneth J. Voss, David McKee, Elisabetta Canuti, André Valente, Susanne Kratzer, Jean-François Berthon, Carlos García-Soto, Kathryn Barker, Frank E. Muller-Karger, Marcel Robert Wernand, Sukru Besiktepe, Mike Grant, Shubha Sathyendranath, Brian Gregory Mitchell, Leonie O'Dowd, P. Jeremy Werdell, Marine and Environmental Sciences Centre [Portugal] (MARE), Instituto Universitário de Ciências Psicológicas, Sociais e da Vida (ISPA), Plymouth Marine Laboratory (PML), Plymouth Marine Laboratory, European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), 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), Instituto Universitário de Ciências Psicológicas, Sociais e da Vida = University Institute of Psychological, Social and Life Sciences (ISPA), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), and Repositório da Universidade de Lisboa
Subjects: In situ, Bio optical, reflectance, 010504 meteorology & atmospheric sciences, Meteorology, irradiance, Remote sensing reflectance, nm, 01 natural sciences, 010309 optics, Set (abstract data type), 0103 physical sciences, Ocean colour, 14. Life underwater, lcsh:Environmental sciences, QC, 0105 earth and related environmental sciences, Remote sensing, lcsh:GE1-350, validation, Physics, GC, model, 010505 oceanography, lcsh:QE1-996.5, scattering, lcsh:Geology, waters, Metadata, products, 13. Climate action, Ocean color, [SDU]Sciences of the Universe [physics], General Earth and Planetary Sciences, Satellite, atlantic, performance
Abstract: A compiled set of in situ data is important to evaluate the quality of ocean-colour satellite-data records. Here we describe the data compiled for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The data were acquired from several sources (MOBY, BOUSSOLE, AERONET-OC, SeaBASS, NOMAD, MERMAID, AMT, ICES, HOT, GeP&CO), span between 1997 and 2012, and have a global distribution. Observations of the following variables were compiled: spectral remote-sensing reflectances, concentrations of chlorophyll a, spectral inherent optical properties and spectral diffuse attenuation coefficients. The data were from multi-project archives acquired via the open internet services or from individual projects, acquired directly from data providers. Methodologies were implemented for homogenisation, quality control and merging of all data. No changes were made to the original data, other than averaging of observations that were close in time and space, elimination of some points after quality control and conversion to a standard format. The final result is a merged table designed for validation of satellite-derived ocean-colour products and available in text format. Metadata of each in situ measurement (original source, cruise or experiment, principal investigator) were preserved throughout the work and made available in the final table. Using all the data in a validation exercise increases the number of matchups and enhances the representativeness of different marine regimes. By making available the metadata, it is also possible to analyse each set of data separately. The compiled data are available at doi:10.1594/PANGAEA.854832 (Valente et al., 2015).
Published: 2016

28. A neural network-based method for merging ocean color and Argo data to extend surface bio-optical properties to depth: Retrieval of the particulate backscattering coefficient

Author: Gd Dall'Olmo, Cédric Jamet, Hervé Claustre, Antoine Poteau, Catherine Schmechtig, Bernard Gentili, Fabrizio D'Ortenzio, Julia Uitz, Raphaëlle Sauzède, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), 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]), Plymouth Marine Laboratory (PML), NERC National Centre for Earth Observation (NCEO), Natural Environment Research Council (NERC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), and Plymouth Marine Laboratory
Subjects: 0106 biological sciences, Surface (mathematics), 010504 meteorology & atmospheric sciences, Meteorology, neural network, Oceanography, 01 natural sciences, ocean color, Geochemistry and Petrology, Robustness (computer science), Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Argo, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Remote sensing, Profiling (computer programming), global ocean, Artificial neural network, 010604 marine biology & hydrobiology, particulate backscattering coefficient, Particulates, Argo profiling float, Geophysics, 13. Climate action, Space and Planetary Science, Ocean color, Environmental science, Satellite, Bio-Argo profiling float
Abstract: International audience; The present study proposes a novel method that merges satellite ocean color bio-optical products with Argo temperature-salinity profiles to infer the vertical distribution of the particulate backscattering coefficient (bbp). This neural network-based method (SOCA-BBP for Satellite Ocean-Color merged with Argo data to infer the vertical distribution of the Particulate Backscattering coefficient) uses three main input components: (1) satellite-based surface estimates of bbp and chlorophyll a concentration matched up in space and time with (2) depth-resolved physical properties derived from temperature-salinity profiles measured by Argo profiling floats and (3) the day of the year of the considered satellite-Argo matchup. The neural network is trained and validated using a database including 4725 simultaneous profiles of temperature-salinity and bio-optical properties collected by Bio-Argo floats, with concomitant satellite-derived products. The Bio-Argo profiles are representative of the global open-ocean in terms of oceanographic conditions, making the proposed method applicable to most open-ocean environments. SOCA-BBP is validated using 20% of the entire database (global error of 21%). We present additional validation results based on two other independent data sets acquired (1) by four Bio-Argo floats deployed in major oceanic basins, not represented in the database used to train the method; and (2) during an AMT (Atlantic Meridional Transect) field cruise in 2009. These validation tests based on two fully independent data sets indicate the robustness of the predicted vertical distribution of bbp. To illustrate the potential of the method, we merged monthly climatological Argo profiles with ocean color products to produce a depth-resolved climatology of bbp for the global ocean.
Published: 2016

29. Understanding the seasonal dynamics of phytoplankton biomass and the deep chlorophyll maximum in oligotrophic environments: A Bio-Argo float investigation

Author: Julia Uitz, Fabrizio D'Ortenzio, Alexandre Mignot, Xiaogang Xing, Hervé Claustre, Antoine Poteau, Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, 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), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), 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: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, Global and Planetary Change, Chlorophyll a, Deep chlorophyll maximum, geography, geography.geographical_feature_category, Mixed layer, chemistry.chemical_compound, Oceanography, Mediterranean sea, chemistry, 13. Climate action, Ocean gyre, Phytoplankton, Environmental Chemistry, Environmental science, Photic zone, 14. Life underwater, Argo, General Environmental Science
Abstract: International audience; We deployed four Bio-Argo profiling floats in various oligotrophic locations of the Pacific subtropical gyres and Mediterranean Sea to address the seasonal phytoplankton dynamics in the euphotic layer and explore its dependence on light regime dynamics. Results show that there is a similar phytoplankton biomass seasonal pattern in the four observed oceanic regions. In the lower part of the euphotic layer, the seasonal displacement of the deep chlorophyll maximum (DCM) is light driven. During winter, the chlorophyll a concentration ([Chl a]) always increases in the upper euphotic mixed layer. This increase always results from a photoacclimation to the reduced irradiance. Depending on the location, however, the concentration can also be associated with an actual increase in biomass. The winter increase in [Chl a] results in an increase in irradiance attenuation that impacts the position of the isolume (level where the daily integrated photon flux is constant) and DCM, which becomes shallower. In summer when the [Chl a] in the upper layer decreases along with light attenuation, the DCM deepens and becomes closer to (and sometimes reaches) the nitracline, which enhances the phytoplankton biomass at the DCM. The bio-optical mechanisms and their relationship to light regimes that are revealed by the time series appear to be generic and potentially characteristic of all of the areas where a DCM forms, which is 50% of the open ocean.
Published: 2014

30. Seasonal variations of bio-optical properties and their interrelationships observed by Bio-Argo floats in the subpolar North Atlantic

Author: Julia Uitz, Hervé Claustre, Haili Wang, Xiaogang Xing, Antoine Poteau, Alexandre Mignot, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Bio optical, biology, Spring bloom, Seasonality, Oceanography, biology.organism_classification, medicine.disease, Geophysics, Diatom, 13. Climate action, Space and Planetary Science, Geochemistry and Petrology, Attenuation coefficient, Phytoplankton, Earth and Planetary Sciences (miscellaneous), Particle backscattering, medicine, Environmental science, Argo, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; Based on in situ data sets collected using two Bio-Argo floats deployed in the subpolar North Atlantic from June 2008 to May 2010, the present study focuses on the seasonal variability of three bio-optical properties, i.e., chlorophyll-a concentration ([Chla]), particle backscattering coefficient at 532 nm (b(bp)(532)), and particle beam attenuation coefficient at 660 nm (c(p)(660)). In addition, the interrelationships among these properties are examined. Our results show that: (1) [Chla], b(bp)(532) and c(p)(660) are largely well coupled with each other in the upper layer, all being minimum in mid-winter (January) and maximum in summer; (2) the backscattering coefficient presents an abrupt increase in late summer in the Icelandic Basin, likely due to a large contribution of coccolithophores following the diatom spring bloom; (3) the intercorrelations between the three bio-optical properties are basically consistent with previous studies; (4) seasonal variation in the of [Chla] to c(p)(660) ratio exhibits a clear light-dependence, most likely due to the phytoplankton photoacclimation.
Published: 2014

31. Bio-Argo: qualification of sensors and evaluation of their factory calibrations

Author: Antoine Poteau, Hervé Claustre, Ortenzio, Fabrizio D., Christophe Penkerc'H, Edouard Leymarie, Grigor Obolensky, Florent Besson, 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), Poteau, Antoine, 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: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2013

32. SEASONAL VARIABILITY OF PHYTOPLANKTON AND PRIMARY PRODUCTION IN THE SOUTH PACIFIC GYRE

Author: Alexandre Mignot, Hervé Claustre, Ortenzio, Fabrizio D., Antoine Poteau, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Grigorov, Ivo, 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: fungi, [SDU.STU.OC] Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: participant; The subtropical gyres represent 40% of the total ocean. They have been considered, since a long time, as steady state biological desert due to low nutrients and phytoplankton biomass throughout the year. Primary production (carbon uptake by phytoplankton) is low too in these regions, but as these structures are huge, it makes the total contribution to ocean primary production important. The South Pacific gyre is considered to be the place where the phytoplankton biomass is the lowest in the global ocean. This area remains poorly sampled and studied, that's why the seasonal variability of phytoplankton, primary production and physical forcing remains unclear. By using in-situ bio-optical profiling float capable to measure physical parameters (temperature and salinity) and proxy of the phytoplankton biomass in the water column, we acquired one year of data near the eastern islands (in the middle of the South Pacific gyre). We found a seasonal variability of the phytoplankton biomass and the carbon flux. This variability is driven by the vertical structure density of the ocean, from very low phytoplankton biomass and carbon uptake in winter (due to the mixing of the water column) to low phytoplankton biomass and carbon uptake in summer (associated with strong stratification). Studying the interaction between the physical forcing and phytoplankton biomass in the subtropical gyres is essential. Any increase in sea water temperature will change the stratification of the water column and thus affect the annual carbon fluxes budget.
Published: 2010

33. Light absorption properties and absorption budget of Southeast Pacific waters

Author: Fanny Tièche, Hervé Claustre, Annick Bricaud, Marcel Babin, Josephine Ras, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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: 0106 biological sciences, Atmospheric Science, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Soil Science, Aquatic Science, Oceanography, 01 natural sciences, Geochemistry and Petrology, Ocean gyre, Phytoplankton, Earth and Planetary Sciences (miscellaneous), Photic zone, 14. Life underwater, Absorption (electromagnetic radiation), [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, geography, geography.geographical_feature_category, Ecology, 010604 marine biology & hydrobiology, Paleontology, Biogeochemistry, Forestry, Colored dissolved organic matter, Geophysics, 13. Climate action, Space and Planetary Science, Environmental science, Upwelling
Abstract: International audience; Absorption coefficients of phytoplankton, nonalgal particles (NAPs), and colored dissolved organic matter (CDOM), and their relative contributions to total light absorption, are essential variables for bio-optical and biogeochemical models. However, their actual variations in the open ocean remain poorly documented, particularly for clear waters because of the difficulty in measuring very low absorption coefficients. The Biogeochemistry and Optics South Pacific Experiment (BIOSOPE) cruise investigated a large range of oceanic regimes, from mesotrophic waters around the Marquesas Islands to hyperoligotrophic waters in the subtropical gyre and eutrophic waters in the upwelling area off Chile. The spectral absorption coefficients of phytoplankton and NAPs were determined using the filter technique, while the CDOM absorption coefficients were measured using a 2 m capillary waveguide. Over the whole transect, the absorption coefficients of both dissolved and particulate components covered approximately two orders of magnitude; in the gyre, they were among the lowest ever reported for open ocean waters. In the oligotrophic and mesotrophic waters, absorption coefficients of phytoplankton and NAPs were notably lower than those measured in other oceanic areas with similar chlorophyll contents, indicating some deviation from the standard chlorophyll-absorption relationships. The contribution of absorption by NAPs to total particulate absorption showed large vertical and horizontal variations. CDOM absorption coefficients covaried with algal biomass, albeit with a high scatter. The spectral slopes of both NAP and CDOM absorption revealed structured spatial variability in relation with the trophic conditions. The relative contributions of each component to total nonwater absorption were (at a given wavelength) weakly variable over the transect, at least within the euphotic layer.
Published: 2010

34. Extreme diversity in noncalcifying haptophytes explains a major pigment paradox in open oceans

Author: Hui Liu, Hervé Claustre, Julia Uitz, Colomban de Vargas, Ian Probert, Fabrice Not, Stéphane Aris-Brosou, Miguel J. Frada, Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Evolution des Protistes et Ecosystèmes Pélagiques (EPEP), Adaptation et diversité en milieu marin (AD2M), 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)-Station biologique de Roscoff [Roscoff] (SBR), 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 d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Diversité et Interactions au sein du Plancton Océanique (DIPO), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [SDV]Life Sciences [q-bio], Biodiversity, Photosynthetic pigment, Biology, Cyanobacteria, Haptophyta, 01 natural sciences, Haptophyte, 03 medical and health sciences, chemistry.chemical_compound, Phytoplankton, Photic zone, 14. Life underwater, Phylogeny, 030304 developmental biology, protistan biodiversity, 0303 health sciences, Multidisciplinary, photosynthesis, Ecology, 010604 marine biology & hydrobiology, Biosphere, Pigments, Biological, Biological Sciences, Plankton, biology.organism_classification, Biological Evolution, chemistry, [SDE]Environmental Sciences, eukaryotic biodiversity
Abstract: The current paradigm holds that cyanobacteria, which evolved oxygenic photosynthesis more than 2 billion years ago, are still the major light harvesters driving primary productivity in open oceans. Here we show that tiny unicellular eukaryotes belonging to the photosynthetic lineage of the Haptophyta are dramatically diverse and ecologically dominant in the planktonic photic realm. The use of Haptophyta-specific primers and PCR conditions adapted for GC-rich genomes circumvented biases inherent in classical genetic approaches to exploring environmental eukaryotic biodiversity and led to the discovery of hundreds of unique haptophyte taxa in 5 clone libraries from subpolar and subtropical oceanic waters. Phylogenetic analyses suggest that this diversity emerged in Paleozoic oceans, thrived and diversified in the permanently oxygenated Mesozoic Panthalassa, and currently comprises thousands of ribotypic species, belonging primarily to low-abundance and ancient lineages of the “rare biosphere.” This extreme biodiversity coincides with the pervasive presence in the photic zone of the world ocean of 19′-hexanoyloxyfucoxanthin (19-Hex), an accessory photosynthetic pigment found exclusively in chloroplasts of haptophyte origin. Our new estimates of depth-integrated relative abundance of 19-Hex indicate that haptophytes dominate the chlorophyll a -normalized phytoplankton standing stock in modern oceans. Their ecologic and evolutionary success, arguably based on mixotrophy, may have significantly impacted the oceanic carbon pump. These results add to the growing evidence that the evolution of complex microbial eukaryotic cells is a critical force in the functioning of the biosphere.
Published: 2009

35. Effects of phytoplankton community on production, size and export of large aggregates: A world-ocean analysis

Author: Louis Legendre, Marc Picheral, Gabriel Gorskya, Lionel Guidi, Lars Stemmann, Frédéric Ibanez, George A. Jackson, Hervé Claustre, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Texas A&M University System, Department of Oceanography [College Station], Texas A&M University [College Station], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), 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), 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)
Subjects: 0106 biological sciences, Mass flux, 010504 meteorology & atmospheric sciences, Mesopelagic zone, 010604 marine biology & hydrobiology, Aquatic Science, Plankton, Oceanography, Atmospheric sciences, 01 natural sciences, Mediterranean sea, Phytoplankton, Environmental science, Particle, Photic zone, 14. Life underwater, Particle size, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: We recorded vertical profiles of size distributions of large particles (> 100 mu m) to a 1000-m depth in the Atlantic, Indian, and Pacific Oceans and in the Mediterranean Sea with the Underwater Video Profiler. Of the 410 profiles used in our analysis, 193 also included temperature, salinity, and high-performance liquid chromatography (HPLC)-resolved pigments, which were used to characterize the size structure of the phytoplankton community. Classification analysis identified six clusters of vertical profiles of size distributions of particles. Each cluster was characterized by the size distribution of its particles in the mesopelagic layer and the change of the particle-size distribution with depth. Clusters with large particles in the mesopelagic layer corresponded to surface waters dominated by microphytoplankton, and those with small particles corresponded to surface waters dominated by picophytoplankton. We estimated the mass flux at 400 m using a relationship between particle size and mass flux. Principal-component regression analysis showed that 68% of the variance of the mass flux at 400 m was explained by the size structure of the phytoplankton community and integrated chlorophyll a in the euphotic zone. We found that coefficient k in the Martin power relationship, which describes the decrease in the vertical mass flux with depth, varies between 0.2 and 1.0 in the world ocean, and we provided an empirical relationship to derive k from the size structure of phytoplankton biomass in the euphotic zone. Biogeochemists and modelers could use that relationship to obtain a realistic description of the downward particle flux instead of using a constant k value as often done.
Published: 2009

36. Submesoscale physical-biogeochemical coupling across the Ligurian current (northwestern Mediterranean) using a bio-optical glider

Author: Louis Marie Prieur, Katarzyna Niewiadomska, Hervé Claustre, Fabrizio D'Ortenzio, 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, Water flow, Mixed layer, 010604 marine biology & hydrobiology, Ocean current, Aquatic Science, Oceanography, 01 natural sciences, Colored dissolved organic matter, 13. Climate action, Downwelling, Upwelling, Photic zone, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: A bio-optical autonomous underwater gliding vehicle, equipped with a conductivity, temperature, depth (CTD) sensor, an oxygen sensor, backscatter meters, chromophoric dissolved organic matter (CDOM) and chlorophyll fluorometers, and upwelling and downwelling radiometers was developed to characterize the biogeochemical response to physical forcing at the submesoscale (1-10 km). Winter data obtained in the northwestern Mediterranean basin in a 50-km transect that crossed the permanent, along-coast Ligurian Current show tight physical-biogeochemical coupling across the Ligurian Current, not observed using other sampling strategies. At the scale of the transect, the various biogeochemical parameters displayed independent behaviors, while at the submesoscale, there was a coherent covariance of these variables, especially in the frontal zone. Near-isopycnal tongues of elevated fluorescence and oxygen concentration were recorded down to a depth of 180 m and are the likely signature of a converging horizontal and downwelled water flow. Local anomalies in a horizontal section well below the mixed-layer depth are likely representative of downwelled waters from the euphotic layer. Intrusions of elevated CDOM concentrations together with signatures of smaller particles are the likely features of a local divergence and upwelled waters from subjacent aphotic layers. These are particularly apparent in the form of local anomalies in a horizontal section within the mixed layer. Similar tongues were observed in data from subsequent glider deployments. Such biogeochemical signatures enable the identification of upward and downward physical motions not observed by other technologies, reinforcing the need for coupled high-resolution physical-biogeochemical studies, not only for investigating biogeochemical processes themselves but also for resolving physical processes at these scales.
Published: 2008

37. Gross community production and metabolic balance in the South Pacific Gyre, using a non intrusive bio-optical method

Author: Yannick Huot, Hervé Claustre, Bernard Gentili, Ingrid Obernosterer, D. Tailliez, Marlon R. Lewis, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Laboratoire d'océanographie biologique de Banyuls (LOBB), 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Oceanography [Halifax] (DO), Dalhousie University [Halifax], Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:Life, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Context (language use), 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 03 medical and health sciences, Water column, Ocean gyre, lcsh:QH540-549.5, Dissolved organic carbon, Photic zone, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Diel vertical migration, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, 0105 earth and related environmental sciences, Earth-Surface Processes, South Pacific Gyre, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010604 marine biology & hydrobiology, lcsh:QE1-996.5, lcsh:Geology, lcsh:QH501-531, Heterotrophic Processes, Oceanography, 13. Climate action, Environmental science, lcsh:Ecology
Abstract: The very clear waters of the South Pacific Gyre likely constitute an end-member of oligotrophic conditions which remain essentially unknown with respect to its impact on carbon fixation and exportation. We describe a non-intrusive bio-optical method to quantify the various terms of a production budget (Gross community production, community losses, net community production) in this area. This method is based on the analysis of the diel cycle in Particulate Organic Carbon (POC), derived from high frequency measurements of the particle attenuation coefficient cp. We report very high integrated rates of Gross Community Production within the euphotic layer (average of 846±484 mg C m−2 d−1 for 17 stations) that are far above any rates determined using incubation techniques for such areas. Furthermore we show that the daily production of POC is essentially balanced by the losses so that the system cannot be considered as net heterotrophic. Our results thus agree well with geochemical methods, but not with incubation studies based on oxygen methods. We stress to the important role of deep layers, below the euphotic layer, in contributing to carbon fixation when incident irradiance at the ocean surface is high (absence of cloud coverage). These deep layers, not considered up to know, might fuel part of the heterotrophic processes in the upper layer, including through dissolved organic carbon. We further demonstrate that, in these extremely clear and stratified waters, integrated gross community production is proportional to the POC content and surface irradiance via an efficiency index ψ GCP*, the water column cross section for Gross Community Production. We finally discuss our results in the context of the role of oligotrophic gyre in the global carbon budget and of the possibility of using optical proxies from space for the development of growth community rather than primary production global models.
Published: 2008

38. Heterotrophic bacterial production in the eastern South Pacific: longitudinal trends and coupling with primary production

Author: Solange Duhamel, Ingrid Obernosterer, Thierry Moutin, Osvaldo Ulloa, F. Van Wambeke, Hervé Claustre, Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines (LMGEM), Centre National de la Recherche Scientifique (CNRS)-Université de la Méditerranée - Aix-Marseille 2, Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie biologique de Banyuls (LOBB), 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Departmento de Oceanografía & Centro de Investigación Oceanográfica en el Pacífico Sur-Oriental, Universidad de Concepción [Chile], Géoazur (GEOAZUR 6526), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines ( LMGEM ), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique ( CNRS ), Observatoire océanologique de Banyuls ( OOB ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'océanographie biologique de Banyuls ( LOBB ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'océanographie et de biogéochimie ( LOB ), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Géoazur ( GEOAZUR ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Universidad de Concepción - University of Concepcion [Chile], Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, lcsh:Life, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Subtropics, Biology, [ PHYS.ASTR.CO ] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Ocean gyre, lcsh:QH540-549.5, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Temperate climate, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Photic zone, 14. Life underwater, Transect, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], 0105 earth and related environmental sciences, Earth-Surface Processes, South Pacific Gyre, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010604 marine biology & hydrobiology, fungi, lcsh:QE1-996.5, Biogeochemistry, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, lcsh:Geology, lcsh:QH501-531, Oceanography, Upwelling, lcsh:Ecology
Abstract: Spatial variation of heterotrophic bacterial production and phytoplankton primary production were investigated across the eastern South Pacific Ocean (−141° W, −8° S to −72° W, −35° S) in November–December 2004. Bacterial production (3H leucine incorporation) integrated over the euphotic zone encompassed a wide range of values, from 43 mg C m−2 d−1 in the hyper-oligotrophic South Pacific Gyre to 392 mg C m−2 d−1 in the upwelling off Chile. In the gyre (120° W, 22° S) records of low phytoplankton biomass (7 mg Total Chla m−2) were obtained and fluxes of in situ 14C-based particulate primary production were as low as 153 mg C m−2 d−1, thus equal to the value considered as a limit for primary production under strong oligotrophic conditions. Average rates of 3H leucine incorporation rates, and leucine incorporation rates per cell (5–21 pmol l−1 h−1 and 15–56×10−21 mol cell−1 h−1, respectively) determined in the South Pacific gyre, were in the same range as those reported for other oligotrophic subtropical and temperate waters. Fluxes of dark community respiration, determined at selected stations across the transect varied in a narrow range (42–97 mmol O2 m−2 d−1), except for one station in the upwelling off Chile (245 mmol O2 m−2 d−1). Bacterial growth efficiencies varied between 5 and 38%. Bacterial carbon demand largely exceeded 14C particulate primary production across the South Pacific Ocean, but was lower or equal to gross community production.
Published: 2008

39. Relating phytoplankton photophysiological properties to community structure on large scales

Author: F. Bruyant, Marcel Babin, Yannick Huot, Hervé Claustre, Julia Uitz xUitz, 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), Département de géomatique appliquée [Sherbrooke] (UdeS), Université de Sherbrooke (UdeS), Observatoire océanologique de Villefranche-sur-mer (OOVM), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Hydrology, Biomass (ecology), 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Community structure, Irradiance, Magnitude (mathematics), Pelagic zone, Aquatic Science, Biology, Oceanography, Atmospheric sciences, 01 natural sciences, Water column, 13. Climate action, Phytoplankton, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Trophic level
Abstract: International audience; We analyzed a large dataset of simultaneous measurements of phytoplankton pigments, spectral specific absorption coefficient for phytoplankton [a*(lambda)], and photosynthesis versus irradiance (P versus E) curve parameters to examine the possible relationships between phytoplankton community structure and photophysiological properties at large spatial scales. Data were collected in various regions, mostly covering the trophic gradient encountered in the world's open ocean. The community composition is described in terms of biomass of three phytoplankton classes, determined using specific biomarker pigments. We present a general empirical model that describes the dependence of algal photophysiology on both the community composition and the relative irradiance within the water column (essentially reflecting photoacclimation). The application of the model to the in situ dataset enables the identification of vertical profiles of photophysiological properties for each phytoplankton class. The class-specific a*(lambda) obtained are consistent with results from the literature and with previous models developed for small and large cells, both in terms of the absolute values and the vertical patterns. Similarly, for the class-specific P versus E curve parameters, the magnitude and vertical distribution obtained with this method are coherent with previous observations. Large cells (mainly diatoms) may be more efficient in carbon storage than smaller cells, whereas their yield of light absorption is lower. We anticipate that such photophysiological parameterizations can improve primary production models by providing estimates of primary production that are specific to different phytoplankton classes on large scale.
Published: 2008

40. Rarely reported dinoflagellates of the genera Ceratium, Gloeodinium, Histioneis, Oxytoxum and Prorocentrum (Dinophyceae) from the open southeast Pacific Ocean

Author: Hervé Claustre, Fernando Gómez, Sami Souissi, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - 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)-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), and 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])
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, biology, Pyrrhophyta, Ecology, 010604 marine biology & hydrobiology, Exuviaella, Gloeodinium, Aquatic Science, Oceanography, biology.organism_classification, 01 natural sciences, Pacific ocean, Ceratium, phytoplankton, 14. Life underwater, Histiophysis, protist, Histioneis, Humanities, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Dinophyceae
Abstract: Rarely reported dinoflagellates of the genera Ceratium, Gloeodinium, Histioneis, Oxytoxum and Prorocentrum from a ~8000 km transect between the Marquesas Islands Archipelago and the Chilean coast are briefly described and illustrated. Nineteen species of the genus Oxytoxum and seven species of the genus Histioneis were identified to species level. Photographic records of Histioneis hyalina and H. cf. pulchra are for the first time reported. One specimen ascribed to Histiophysis sp., a genus never reported since the first description, is illustrated. Beyond the single-cell specimens of Prorocentrum, a colonial behavior was observed. A small species, identified as Prorocentrum dentatum, was encountered forming rows. Colonies of pairs of ellipsoidal or sphaerical cells embedded in a hyaline matrix have been ascribed to Gloeodinium marinum. Ceratium lanceolatum is for the first time reported in the South Pacific Ocean since the first description. Photographic records of Ceratium carnegiei, C. divaricatum and C. lanceolatum are reported
Published: 2008

41. The origin and global distribution of second order variability in satellite ocean color and its potential applications to algorithm development

Author: Bernard Gentili, P. Jeremy Werdell, Hervé Claustre, Yannick Huot, Catherine A. Brown, Département de géomatique appliquée [Sherbrooke] (UdeS), Université de Sherbrooke (UdeS), NASA Goddard Space Flight Center (GSFC), 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Soil Science, Geology, 01 natural sciences, 010309 optics, Colored dissolved organic matter, 13. Climate action, Ocean color, Attenuation coefficient, 0103 physical sciences, Dispersion (optics), Trend surface analysis, Environmental science, Satellite, Statistical dispersion, 14. Life underwater, Computers in Earth Sciences, Absorption (electromagnetic radiation), Algorithm, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Remote sensing
Abstract: International audience; Empirical algorithms based on first order relationships between ocean color and the chlorophyll concentration ([ChI]; mg m(-3)) are widely used, but cannot explain the statistical dispersion or ``anomalies'' around the mean trends. We use an empirical approach that removes the first order effects of [ChI] from satellite ocean color, thus allowing us to quantify the impact on the ocean color signal of optical anomalies that vary independently of the global mean trends with remotely sensed [ChI]. We then present statistical and modeling analyses to interpret the observed anomalies in terms of their optical sources (i.e. absorption and backscattering coefficients). We identify two main sources of second order variability for a given [ChI]: 1) the amount of non-algal absorption, especially due to colored dissolved organic matter; and 2) the amplitude of the backscattering coefficient of particles. The global distribution of the anomalies displays significant regional and seasonal trends, providing important information for characterizing the marine optical environment and for inferring biogeochemical influences. We subsequently use our empirically determined anomalies to estimate the backscattering coefficient of particles and the combined absorption coefficient for colored detrital and dissolved materials. This purely empirical approach provides an independent assessment of second order optical variability for comparison with existing methods that are generally based on semi-analytical models. (C) 2008 Elsevier Inc. All rights reserved.
Published: 2008

42. Growth and specific P-uptake rates of bacterial and phytoplanktonic communities in the Southeast Pacific (BIOSOPE cruise)

Author: B. A. S. Van Mooy, F. Van Wambeke, Hervé Claustre, Solange Duhamel, P. Rimmelin, Patrick Raimbault, Thierry Moutin, Laboratoire d'océanographie et de biogéochimie ( LOB ), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines ( LMGEM ), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique ( CNRS ), Department of Marine Chemistry and Geochemistry ( WHOI ), Woods Hole Oceanographic Institution ( WHOI ), Géoazur ( GEOAZUR ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire océanologique de Villefranche-sur-mer ( OOVM ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines (LMGEM), Centre National de la Recherche Scientifique (CNRS)-Université de la Méditerranée - Aix-Marseille 2, Department of Marine Chemistry and Geochemistry (WHOI), Woods Hole Oceanographic Institution (WHOI), Géoazur (GEOAZUR 6526), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Nice Sophia Antipolis (1965 - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, lcsh:Life, Heterotroph, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Biology, [ PHYS.ASTR.CO ] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], lcsh:QH540-549.5, Botany, Phytoplankton, [ SDU.ENVI ] Sciences of the Universe [physics]/Continental interfaces, environment, Photic zone, 14. Life underwater, Autotroph, Picoplankton, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], 0105 earth and related environmental sciences, Earth-Surface Processes, Trophic level, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Deep chlorophyll maximum, Biomass (ecology), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010604 marine biology & hydrobiology, lcsh:QE1-996.5, [ SDU.STU ] Sciences of the Universe [physics]/Earth Sciences, lcsh:Geology, lcsh:QH501-531, Environmental chemistry, lcsh:Ecology
Abstract: Predicting heterotrophic bacteria and phytoplankton specific growth rates (μ ) is of great scientific interest. Many methods have been developed in order to assess bacterial or phytoplankton μ. One widely used method is to estimate μ from data obtained on biomass or cell abundance and rates of biomass or cell production. According to Kirchman (2002), the most appropriate approach for estimating μ is simply to divide the production rate by the biomass or cell abundance estimate. Most methods using this approach to estimate μ are based on carbon (C) incorporation rates and C biomass measurements. Nevertheless it is also possible to estimate μ using phosphate (P) data. We showed that particulate phosphate (PartP) can be used to estimate biomass and that the P uptake rate to PartP ratio can be employed to assess μ. Contrary to other methods using C, this estimator does not need conversion factors and provides an evaluation of μ for both autotrophic and heterotrophic organisms. We report values of P-based μ in three size fractions (0.2–0.6; 0.6–2 and >2 μm) along a Southeast Pacific transect, over a wide range of P-replete trophic status. P-based μ values were higher in the 0.6–2 μm fraction than in the >2 μm fraction, suggesting that picoplankton-sized cells grew faster than the larger cells, whatever the trophic regime encountered. Picoplankton-sized cells grew significantly faster in the deep chlorophyll maximum layer than in the upper part of the photic zone in the oligotrophic gyre area, suggesting that picoplankton might outcompete >2 μm cells in this particular high-nutrient, low-light environment. P-based μ attributed to free-living bacteria (0.2-0.6 μm) and picoplankton (0.6–2 μm) size-fractions were relatively low (0.11±0.07 d−1 and 0.14±0.04 d−1, respectively) in the Southeast Pacific gyre, suggesting that the microbial community turns over very slowly.
Published: 2007

43. Contribution of picoplankton to the total particulate organic carbon concentration in the eastern South Pacific

Author: Yannick Huot, Gadiel Alarcón, Dominique Marie, C. Grob, Hervé Claustre, Osvaldo Ulloa, Graduate Programme in Oceanography, Universidad de Concepción - University of Concepcion [Chile], Department of Oceanography, Center for Oceanographic Research in the Eastern South Pacific (FONDAP-COPAS), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Universidad de Concepción [Chile], and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:Life, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Water column, lcsh:QH540-549.5, Phytoplankton, 14. Life underwater, Picoplankton, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Earth-Surface Processes, South Pacific Gyre, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010604 marine biology & hydrobiology, lcsh:QE1-996.5, Bacterioplankton, biology.organism_classification, lcsh:Geology, lcsh:QH501-531, Oceanography, 13. Climate action, Upwelling, lcsh:Ecology, Prochlorococcus, Equivalent spherical diameter
Abstract: Prochlorococcus, Synechococcus, picophytoeukaryotes and bacterioplankton abundances and contributions to the total particulate organic carbon concentration, derived from the total particle beam attenuation coefficient (cp), were determined across the eastern South Pacific between the Marquesas Islands and the coast of Chile. All flow cytometrically derived abundances decreased towards the hyper-oligotrophic centre of the gyre and were highest at the coast, except for Prochlorococcus, which was not detected under eutrophic conditions. Temperature and nutrient availability appeared important in modulating picophytoplankton abundance, according to the prevailing trophic conditions. Although the non-vegetal particles tended to dominate the cp signal everywhere along the transect (50 to 83%), this dominance seemed to weaken from oligo- to eutrophic conditions, the contributions by vegetal and non-vegetal particles being about equal under mature upwelling conditions. Spatial variability in the vegetal compartment was more important than the non-vegetal one in shaping the water column particle beam attenuation coefficient. Spatial variability in picophytoplankton biomass could be traced by changes in both total chlorophyll a (i.e. mono + divinyl chlorophyll a) concentration and cp. Finally, picophytoeukaryotes contributed ~38% on average to the total integrated phytoplankton carbon biomass or vegetal attenuation signal along the transect, as determined by size measurements (i.e. equivalent spherical diameter) on cells sorted by flow cytometry and optical theory. Although there are some uncertainties associated with these estimates, the new approach used in this work further supports the idea that picophytoeukaryotes play a dominant role in carbon cycling in the upper open ocean, even under hyper-oligotrophic conditions.
Published: 2007

44. Two High-Nutrient Low-Chlorophyll phytoplankton assemblages: the tropical central Pacific and the offshore Perú-Chile Current

Author: Sami Souissi, Patrick Raimbault, Hervé Claustre, Fernando Gómez, Ecosystèmes Littoraux et Cotiers, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Temperature salinity diagrams, lcsh:Life, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Biology, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], lcsh:QH540-549.5, Phytoplankton, Temperate climate, 14. Life underwater, Transect, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Ecology, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, biology.organism_classification, High-Nutrient, low-chlorophyll, lcsh:Geology, lcsh:QH501-531, Oceanography, Diatom, Archipelago, Submarine pipeline, lcsh:Ecology
Abstract: The phytoplankton (>15 μm) composition and abundance was investigated along a ~8000 km transect between the Marquesas Islands Archipelago and the Chilean coasts off Concepción. In the southern limit of the central Equatorial Pacific (at 8° S, 141° W), in High-Nutrient Low-Chlorophyll (HNLC) warm waters, the microphytoplankton assemblage was dominated by the lightly silicified diatoms Pseudo-nitzschia delicatissima and Rhizosolenia bergonii. The morphology of these species, a small pennate diatom that exhibited a tendency to form "ball of needles" clusters and large centric diatom (>500 μm long), are interpreted as two anti-grazing strategies in an environment dominated by small micrograzers. Surprisingly, this a priori typical HNLC phytoplankton assemblage was also found in the temperate offshore waters of the Perú-Chile Current between 2000 and 600 km off Chile. This observation suggests that a common set of environmental factors (obviously other than temperature and salinity) are responsible for the establishment and maintaining of this distinctive phytoplankton in these geographically and hydrologically distant regions. Both regions are characterized by a surface nitrate-silicic acid ratio ranging from 1–3. Occasionally Rhizosolenia bergonii showed frustules anomalously fragmented, likely the result of extreme weakly silicified phytoplankton. We suggest that silicon deficiency may be responsible of the occurrence of HNLC phytoplankton assemblage in the tropical central Pacific as well as the offshore Perú-Chile Current during the austral summer.
Published: 2007

45. Optical properties of the 'clearest' natural waters

Author: Fanny Tièche, André Morel, Bernard Gentili, Annick Bricaud, Hervé Claustre, Josephine Ras, Marcel Babin, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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: 0106 biological sciences, Absorption of water, Materials science, 010504 meteorology & atmospheric sciences, business.industry, 010604 marine biology & hydrobiology, Attenuation, Irradiance, Analytical chemistry, Aquatic Science, Particulates, Oceanography, 01 natural sciences, Optics, 13. Climate action, Attenuation coefficient, Radiometry, Seawater, business, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, South Pacific Gyre
Abstract: Optical measurements within both the visible and near ultraviolet (UV) parts of the spectrum (305-750 nm) were recently made in hyperoligotrophic waters in the South Pacific gyre (near Easter Island). The diffuse attenuation coefficients for downward irradiance, K-d(lambda), and the irradiance reflectances, R(lambda), as derived from hyperspectral (downward and upward) irradiance measurements, exhibit very uncommon values that reflect the exceptional clarity of this huge water body. The K-d(lambda) values observed in the UV domain are even below the absorption coefficients found in current literature for pure water. The R(A) values (beneath the surface) exhibit a maximum as high as 13% around 390 nm. From these apparent optical properties, the absorption and backscattering coefficients can be inferred by inversion and compared to those of (optically) pure seawater. The total absorption coefficient (a(tot)) exhibits a flat minimum (similar to 0.007 m(-1)) around 410-420 nm, about twice that of pure water. At 310 nm, a(tot) may be as low as 0.045 m(-1), i.e., half the value generally accepted for pure water. The particulate absorption is low compared to those of yellow substance and water and represents only similar to 15% of a(tot) in the 305-420-nm domain. The backscattering coefficient is totally dominated by that of water molecules in the UV domain. Because direct laboratory determinations of pure water absorption in the UV domain are still scarce and contradictory, we determine a tentative upper bound limit for this elusive coefficient as it results from in situ measurements.
Published: 2007

46. Partitioning total spectral absorption in phytoplankton and colored detrital material contributions

Author: Marcel Babin, Hervé Claustre, Kadija Oubelkheir, Annick Bricaud, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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: 0106 biological sciences, Absorption of water, 010504 meteorology & atmospheric sciences, Chemistry, 010604 marine biology & hydrobiology, Analytical chemistry, Mineralogy, Ocean Engineering, 01 natural sciences, Spectral line, Colored dissolved organic matter, Colored, Phytoplankton, Spectral resolution, Absorption (electromagnetic radiation), Image resolution, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: A method based on spectral information is used to derive spectral absorption coefficients of phytoplankton a(phi)(lambda) and colored detrital material, CDM, which includes non-algal particle and colored dissolved organic matter, a(CDM)(lambda), from total minus water absorption coefficients measurements. This method is first validated over a dataset of more than 300 simultaneous measurements of phytoplankton, non-algal particle, and colored dissolved organic matter absorption coefficients spectra acquired with a laboratory spectrophotometer in various oceanic and coastal European waters. The validation is presented for measurements made with a high spectral resolution (hyper-spectral case), and a limited spectral resolution (multi-spectral case)-the case of most devices routinely used for in situ profiling, such as the WETLabs ac-9. In order to examine the various sources of error in the method, we test its performance considering various levels of a priori knowledge of phytoplankton absorption properties over the study area: for each site, over each region, or over a global dataset only. When the method is applied to the multi-spectral case without introducing any ``local'' information on phytoplankton absorption properties, we obtain a good performance with a relative Root Mean Square Error equal to 17.8%, 14.6%, and 40.7% for a(CDM)(412), the CDM exponential slope, and a(phi)(440), respectively. Finally, the partitioning method is directly applied to in situ profiles of total minus water spectral absorption coefficient measured with an ac-9 in various oceanic Mediterranean waters, allowing the in situ description of CDM and phytoplankton absorption coefficients with a high spatial resolution.
Published: 2007

47. Retrieval of pigment concentrations and size structure of algal populations from their absorption spectra using multilayered perceptrons

Author: David Blondeau-Patissier, Michel Crépon, Hervé Claustre, Carlos Mejia, Annick Bricaud, Sylvie Thiria, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), 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), 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), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-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), 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)-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)
Subjects: 0106 biological sciences, Chlorophyll b, Chlorophyll a, 010504 meteorology & atmospheric sciences, Materials Science (miscellaneous), Photosynthesis, 01 natural sciences, Industrial and Manufacturing Engineering, chemistry.chemical_compound, Optics, Phytoplankton, 14. Life underwater, Business and International Management, Absorption (electromagnetic radiation), Chromatography, High Pressure Liquid, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Mathematics, business.industry, 010604 marine biology & hydrobiology, Osmolar Concentration, Hyperspectral imaging, Pigments, Biological, chemistry, Spectrophotometry, Ocean color, Chlorophyll, Neural Networks, Computer, business
Abstract: International audience; Spectral absorption coefficients of phytoplankton can now be derived, under some assumptions, from hyperspectral ocean color measurements and thus become accessible from space. In this study, multilayer perceptrons have been developed to retrieve information on the pigment composition and size structure of phytoplankton from these absorption spectra. The retrieved variables are the main pigment groups (chlorophylls a, b, c, and photosynthetic and nonphotosynthetic carotenoids) and the relative contributions of three algal size classes (pico-, nano-, and microphytoplankton) to total chlorophyll a. The networks have been trained, tested, and validated using more than 3700 simultaneous absorption and pigment measurements collected in the world ocean. Among pigment groups, chlorophyll a is the most accurately retrieved (average relative errors of 17% and 16% for the test and validation data subsets, respectively), while the poorest performances are found for chlorophyll b (average relative errors of 51% and 40%). Relative contributions of algal size classes to total chlorophyll a are retrieved with average relative errors of 19% to 33% for the test subset and of 18% to 47% for the validation subset. The performances obtained for the validation data, showing no strong degradation with respect to test data, suggest that these neural networks might be operated with similar performances for a large variety of marine areas. (c) 2007 Optical Society of America.
Published: 2007

48. Vertical distribution of phytoplankton communities in open ocean: An assessment based on surface chlorophyll

Author: Julia Uitz, André Morel, Hervé Claustre, Stanford B. Hooker, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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: 0106 biological sciences, Atmospheric Science, Chlorophyll a, 010504 meteorology & atmospheric sciences, Soil Science, Context (language use), Aquatic Science, Oceanography, 01 natural sciences, chemistry.chemical_compound, Geochemistry and Petrology, Nanophytoplankton, Phytoplankton, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, Picoplankton, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Biomass (ecology), Ecology, 010604 marine biology & hydrobiology, Paleontology, Forestry, Plankton, Geophysics, chemistry, Space and Planetary Science, Ocean color, Environmental science
Abstract: International audience; The present study examines the potential of using the near-surface chlorophyll a concentration ([Chla](surf)), as it can be derived from ocean color observation, to infer the column-integrated phytoplankton biomass, its vertical distribution, and ultimately the community composition. Within this context, a large High-Performance Liquid Chromatography (HPLC) pigment database was analyzed. It includes 2419 vertical pigment profiles, sampled in case 1 waters with various trophic states (0.03-6 mg Chla m(-3)). The relationships between [Chla](surf) and the chlorophyll a vertical distribution, as previously derived by Morel and Berthon (1989), are fully confirmed. This agreement makes it possible to go further and to examine if similar relationships between [Chla](surf) and the phytoplankton assemblage composition along the vertical can be derived. Thanks to the detailed pigment composition, and use of specific pigment biomarkers, the contribution to the local chlorophyll a concentration of three phytoplankton groups can be assessed. With some cautions, these groups coincide with three size classes, i.e., microplankton, nanoplankton and picoplankton. Corroborating previous regional findings (e.g., large species dominate in eutrophic environments, whereas tiny phytoplankton prevail in oligotrophic zones), the present results lead to an empirical parameterization applicable to most oceanic waters. The predictive skill of this parameterization is satisfactorily tested on a separate data set. With such a tool, the vertical chlorophyll a profiles of each group can be inferred solely from the knowledge of [Chla](surf). By combining this tool with satellite ocean color data, it becomes possible to quantify on a global scale the phytoplankton biomass associated with each of the three algal assemblages.
Published: 2006

49. Bio-optical and biogeochemical properties of different trophic regimes in oceanic waters

Author: Hervé Claustre, Marcel Babin, Kadija Oubelkheir, Antoine Sciandra, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), 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: 0106 biological sciences, Chlorophyll a, Biogeochemical cycle, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Biogeochemistry, Aquatic Science, Plankton, Oceanography, 01 natural sciences, Colored dissolved organic matter, chemistry.chemical_compound, chemistry, 13. Climate action, Phytoplankton, Upwelling, Environmental science, 14. Life underwater, Picoplankton, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences
Abstract: To examine the source and magnitude of the variability of bio-optical properties in open ocean, we simultaneously measured inherent optical properties (IOPs) and biogeochemical quantities during late summer from the eutrophic waters of the Moroccan upwelling to the oligotrophic waters of the northwestern Mediterranean and the ultraoligotrophic waters of the eastern Mediterranean. Vertical distributions of spectral absorption and attenuation coefficients were measured with a high-resolution in situ spectrophotometer (WETLabs ac9) together with biogeochemical measurements that included phytoplanktonic pigments and particulate organic carbon concentrations, particle size distributions, and picoplankton abundance. The variability in specific IOPs (i.e., per unit of biogeochemical constituent concentration) was examined, and an optical index of particle size was derived. The fine-scale vertical distributions of various biogeochemical properties were thus described from ac9 profiles. Particle attenuation and carbon budgets, estimated from a combination of optical and biogeochemical measurements, underlie a major contribution of nonalgal stocks in oceanic waters. We show that first-order variations in IOPs in oceanic waters are explained by the trophic state (i.e., chlorophyll a concentration) and that second-order variations are the result of changes in the composition of phytoplankton assemblage, the balance between algal and nonalgal stocks, and lightrelated processes (colored dissolved organic material photo-oxidation and algal photo-adaptation). At the interface between marine optics and biogeochemistry, bio-optical studies (Smith and Baker 1978) aim to characterize the biological and biogeochemical state of natural waters through their optical properties, and to quantify the role of the ocean in global biogeochemical (particularly carbon) budgets. These studies rely on the direct dependence of the water’s inherent optical properties (IOPs) and apparent optical properties on the concentration and nature of optically significant biogeochemical constituents. In open ocean case I waters (Morel and Maritorena 2001 and references therein), these constituents are, by definition, phytoplankton and their accompanying and covarying retinue of material with biological origin, namely nonalgal particles (including biogenous detritus and heterotrophic organisms) and yellow substances (so-called colored dissolved organic material [CDOM]). Thus, optical properties generally are modeled as a function of chlorophyll a concentration (Chl a; used as a proxy for phytoplankton) in generic remote sensing algorithms for case I waters (Morel and Maritorena 2001 and 1
Published: 2005

50. Toward a taxon-specific parameterization of bio-optical models of primary production: A case study in the North Atlantic

Author: Louis Marie Prieur, Thierry Moutin, Ondrej Prasil, Hervé Claustre, Serge Dallot, Davy Merien, Marcel Babin, Josephine Ras, Helena Dousova, Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), University of South Bohemia, Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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: 0106 biological sciences, Atmospheric Science, Chlorophyll a, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Soil Science, Aquatic Science, Oceanography, Atmospheric sciences, Photosynthesis, 01 natural sciences, chemistry.chemical_compound, Water column, Nitrate, Geochemistry and Petrology, Nanophytoplankton, Phytoplankton, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Abiotic component, Hydrology, Biotic component, Ecology, 010604 marine biology & hydrobiology, Paleontology, Forestry, Geophysics, chemistry, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, Environmental science
Abstract: [1] As part of the Programme Ocean Multidisciplinaire Meso Echelle (POMME) in the North Atlantic, an extensive data set of high-pressure liquid chromatography pigment concentrations, phytoplankton absorption coefficients, primary production measurements, and P versus E curves has been acquired. This data set is analyzed with the objective of testing whether photosynthetic performances of natural phytoplankton communities are related to taxonomic characteristics. This objective is addressed in two ways. The first approach concerns the bulk photosynthetic performances of the water column: the water column photosynthetic cross section, ψ*, equals 0.088 m2 gChla−1, i.e., ∼25% higher than the average for the world ocean. Using multiple regression, size-specific values of ψ* are subsequently derived: carbon storage by water column is more efficient with microphytoplankton (ψ* = 0.135 m2 gChla−1) than with nanophytoplankton (0.089 m2 gChla−1) or picophytoplankton (0.064 m2 gChla−1). The second (independent) approach examines the correlations between photophysiological properties and several abiotic and biotic variables. The correlations are weak, if any, between photophysiological properties and abiotic factors (temperature, nitrate concentration, and irradiance), while significant correlations are reported with biotic factors (proportion of the different phytoplankton groups, average size of the phytoplankton assemblage). Our results suggest that when large phytoplankton populations predominate at the expense of smaller ones, the specific absorption coefficient is expectedly lower, while other photophysiological properties αB, PmaxB, and Φcmax, are higher. The agreement between both independent approaches points out that large phytoplankton (essentially diatoms) are potentially more efficient in carbon storage than any other phytoplankton groups on a chlorophyll a or light absorption basis.
Published: 2005

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