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15 results on '"Alexandre Mignot"'

1. Biological production in two contrasted regions of the Mediterranean Sea during the oligotrophic period: An estimate based on the diel cycle of optical properties measured by BGC-Argo profiling floats

Author

Bernard Gentili, Marie Barbieux, Vincent Taillandier, Julia Uitz, Christophe Penkerc'h, Hervé Claustre, Antoine Poteau, Collin S. Roesler, Hubert Loisel, Annick Bricaud, Catherine Schmechtig, Edouard Leymarie, Fabrizio D'Ortenzio, and Alexandre Mignot

Subjects
Total organic carbon, Biomass (ecology), Water column, Oceanography, Mediterranean sea, Phytoplankton, Environmental science, Photic zone, 14. Life underwater, Diel vertical migration, Argo
Abstract

This study assesses marine biological production of organic carbon based on the diel variability of bio-optical properties monitored by two BioGeoChemical-Argo (BGC-Argo) floats. Experiments were conducted in two distinct Mediterranean systems, the Northwestern Ligurian Sea and the Central Ionian Sea during summer months. We derived particulate organic carbon (POC) stock and gross community production integrated within the surface, euphotic and subsurface chlorophyll maximum (SCM) layers, using an existing approach applied to diel cycle measurements of the particulate beam attenuation (cp) and backscattering (bbp) coefficients. The diel cycle of cp provided a robust proxy for quantifying biological production in both systems; that of bbp was comparatively less robust. Derived primary production estimates vary by a factor of 2 depending upon the choice of the bio-optical relationship that converts the measured optical coefficient to POC, which is thus a critical step to constrain. Our results indicate a substantial, yet variable, contribution to the water column production of the SCM layer (16–42%). In the Ligurian Sea, the SCM is a seasonal feature that behaves as a subsurface biomass maximum (SBM) with the ability to respond to episodic abiotic forcing by increasing production. In contrast, in the Ionian Sea, the SCM is permanent, induced by phytoplankton photoacclimation and contributes moderately to water column production. These results emphasize the strong potential for transmissometers deployed on BGC-Argo profiling floats to quantify non-intrusively in situ biological production of organic carbon in the water column of stratified oligotrophic systems with recurring or permanent SCMs, which are widespread features in the global ocean.

Published
2022

2. Modelling the marine ecosystem of Iberia–Biscay–Ireland (IBI) European waters for CMEMS operational applications

Author

Marcos García Sotillo, Tomasz Dabrowski, Elodie Gutknecht, Alexandre Mignot, and Guillaume Reffray

Subjects
Mediterranean climate, lcsh:GE1-350, Biogeochemical cycle, lcsh:Geography. Anthropology. Recreation, Primary production, Biogeochemistry, Current (stream), Ocean dynamics, Oceanography, lcsh:G, Environmental science, Ecosystem, Marine ecosystem, lcsh:Environmental sciences
Abstract

As part of the Copernicus Marine Environment Monitoring Service (CMEMS), a physical–biogeochemical coupled model system has been developed to monitor and forecast the ocean dynamics and marine ecosystem of the European waters and more specifically on the Iberia–Biscay–Ireland (IBI) area. The CMEMS IBI coupled model covers the north-east Atlantic Ocean from the Canary Islands to Iceland, including the North Sea and the western Mediterranean, with a NEMO-PISCES 1∕36∘ model application. The coupled system has been providing 7 d weekly ocean forecasts for CMEMS since April 2018. Prior to its operational launch, a pre-operational qualification simulation (2010–2016) has allowed assessing the model's capacity to reproduce the main biogeochemical and ecosystem features of the IBI area. The objective of this paper is then to describe the consistency and skill assessment of the PISCES biogeochemical model using this 7-year qualification simulation. The model results are compared with available satellite estimates as well as in situ observations (ICES, EMODnet and BGC-Argo). The simulation successfully reproduces the spatial distribution and seasonal cycles of oxygen, nutrients, chlorophyll a and net primary production, and confirms that PISCES is suitable at such a resolution and can be used for operational analysis and forecast applications. This model system can be a useful tool to better understand the current state and changes in the marine biogeochemistry of European waters and can also provide key variables for developing indicators to monitor the health of marine ecosystems. These indicators may be of interest to scientists, policy makers, environmental agencies and the general public.

Published
2019

3. Towards operational 3D-Var assimilation of chlorophyll Biogeochemical-Argo float data into a biogeochemical model of the Mediterranean Sea

Author

Laura Mariotti, Vincent Taillandier, Gianpiero Cossarini, Alexandre Mignot, Anna Teruzzi, Laura Feudale, Fabrizio D'Ortenzio, Stefano Salon, Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), 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), Istituto di Scienze Marine [La Spezia] (CNR-ISMAR-SP), Istituto di Science Marine (ISMAR ), and Consiglio Nazionale delle Ricerche (CNR)-Consiglio Nazionale delle Ricerche (CNR)

Subjects
Chlorophyll, Mediterranean climate, Atmospheric Science, Biogeochemical cycle, Biogeochemical model, 010504 meteorology & atmospheric sciences, Oceanography, Atmospheric sciences, 01 natural sciences, chemistry.chemical_compound, Mediterranean sea, Data assimilation, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Phytoplankton, Mediterranean Sea, Computer Science (miscellaneous), Marine ecosystem, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Argo, 0105 earth and related environmental sciences, Biogeochemical-Argo float, 010505 oceanography, Geotechnical Engineering and Engineering Geology, chemistry, Environmental science
Abstract

International audience; The emerging availability of Biogeochemical-Argo (BGC-Argo) float data creates new opportunities to combine models and observations in investigations of the interior structures and dynamics of marine ecosystems. An existing variational data assimilation scheme (3DVarBio) has been upgraded and coupled with the Copernicus Marine Environment Monitoring Service biogeochemical model of the Mediterranean Sea to assimilate BGC-Argo chlorophyll profile observations. Our results show that the assimilation of BGC-Argo float data is feasible. Moreover, the proposed data assimilation framework provides significant corrections to the chlorophyll concentrations and is able to consistently readjust the shapes of chlorophyll profiles during surface blooms occurring in winter vertically mixed conditions, and in the case of the summer deep chlorophyll maxima. Sensitivity analysis and diagnostic metrics have been applied to evaluate the impact of assimilation and the relevance of different factors of the 3DVarBio method. A key factor is the observation error that has been tuned on a monthly basis to incorporate the representation error. Different frequencies of the assimilation cycle have been tested: daily or 3-day assimilation fosters the highest skill performances despite the reduced impacts and the increase of computational burden. Considering the present size of the BGC-Argo Mediterranean network (about 15 floats) and the estimated non-homogeneous correlation radius length scale (15.2 km on average), the chlorophyll assimilation can constrain the phytoplankton dynamics along the whole water column over an area up to 10% of the Mediterranean Sea.

Published
2019

4. 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

5. Med-BGC MIP: A Mediterranean Biogeochemical models comparison

Author

Paolo Lazzari, Julien Palmieri, Diego Macias Moy, Alexandre Mignot, Kostas Tsiaras, Susan Kay, Stefano Ciavatta, Jean-Claude Dutay, Solidoro Cosimo, Melika Baklouti, Julien Lamouroux, Camille Richon, Julia Uitz, Loïc Houpert, Samuel Somot, Catherine Schmechtig, Anna Teruzzi, Fabrizio D'Ortenzio, Rémi Pagès, and George S. Triantafyllou

Subjects
Mediterranean climate, Biogeochemical cycle, Oceanography, Environmental science
Abstract

The Mediterranean Sea has been identified as a hotspot for climate change. Furthermore, its very diverse trophic regimes, in such a little area, make it an extremely interesting region from a biogeochemical perspective. Numerous studies aim at better understanding and representing the Mediterrenean dynamics and biogeochemistry through modeling. This is a crucial step in order to predict the future anthropogenic impacts on the Mediterranean Sea and their possible effects on its biogeochemistry, and all what depends on it. The number of models that simulate the Mediterranean biogeochemistry, and the data available to compare with are now sufficient to draw an overall picture of the Mediterranean Sea biogeochemical models state of the art.In this study, we gathered 10 biogeochemical simulations of the Mediterranean Sea, including 8 regional and 2 high-resolution global configurations. The simulations are compared with surface chlorophyll estimates derived from satellite observations; chlorophyll, nitrate, oxygen, and particulate organic carbon concentrations derived from BGC-Argo floats, and phytoplankton group-specific primary production estimated from ocean color satellite observations. Our first aim is to describe and compare all known Mediterranean biogeochemical models, and to highlight their specificity. This should give an insight into the current achievements, and expose what biogeochemical model products are hence available for further ecological analysis. Furthermore, a specific attention is given to how well each model performs in selected regions of the Mediterranean Sea, in order to understand which specific process is needed to adequately represent the different trophic regimes of the Mediterranean Sea.

Published
2021

6. 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

7. Copernicus Marine Service Ocean State Report, Issue 4

Author

Karina von Schuckmann, Pierre-Yves Le Traon, Neville Smith, Ananda Pascual, Samuel Djavidnia, Jean-Pierre Gattuso, Marilaure Grégoire, Glenn Nolan, Signe Aaboe, Enrique Álvarez Fanjul, Lotfi Aouf, Roland Aznar, T. H. Badewien, Arno Behrens, Maristella Berta, Laurent Bertino, Jeremy Blackford, Giorgio Bolzon, Federica Borile, Marine Bretagnon, Robert J.W. Brewin, Donata Canu, Paola Cessi, Stefano Ciavatta, Bertrand Chapron, Thi Tuyet Trang Chau, Frédéric Chevallier, Boriana Chtirkova, Stefania Ciliberti, James R. Clark, Emanuela Clementi, Clément Combot, Eric Comerma, Anna Conchon, Giovanni Coppini, Lorenzo Corgnati, Gianpiero Cossarini, Sophie Cravatte, Marta de Alfonso, Clément de Boyer Montégut, Christian De Lera Fernández, Francisco Javier de los Santos, Anna Denvil-Sommer, Álvaro de Pascual Collar, Paulo Alonso Lourenco Dias Nunes, Valeria Di Biagio, Massimiliano Drudi, Owen Embury, Pierpaolo Falco, Odile Fanton d’Andon, Luis Ferrer, David Ford, H. Freund, Manuel García León, Marcos García Sotillo, José María García-Valdecasas, Philippe Garnesson, Gilles Garric, Florent Gasparin, Marion Gehlen, Ana Genua-Olmedo, Gerhard Geyer, Andrea Ghermandi, Simon A. Good, Jérôme Gourrion, Eric Greiner, Annalisa Griffa, Manuel González, Ismael Hernández-Carrasco, Stéphane Isoard, John J. Kennedy, Susan Kay, Anton Korosov, Kaari Laanemäe, Peter E. Land, Thomas Lavergne, Paolo Lazzari, Jean-François Legeais, Benedicte Lemieux, Bruno Levier, William Llovel, Vladyslav Lyubartsev, Vidar S. Lien, Leonardo Lima, Pablo Lorente, Julien Mader, Marcello G. Magaldi, Ilja Maljutenko, Antoine Mangin, Carlo Mantovani, Veselka Marinova, Simona Masina, Elena Mauri, J. Meyerjürgens, Alexandre Mignot, Robert McEwan, Carlos Mejia, Angélique Melet, Milena Menna, Benoît Meyssignac, Alexis Mouche, Baptiste Mourre, Malte Müller, Giulio Notarstefano, Alejandro Orfila, Silvia Pardo, Elisaveta Peneva, Begoña Pérez-Gómez, Coralie Perruche, Monika Peterlin, Pierre-Marie Poulain, Nadia Pinardi, Yves Quilfen, Urmas Raudsepp, Richard Renshaw, Adèle Révelard, Emma Reyes-Reyes, M. Ricker, Pablo Rodríguez-Rubio, Paz Rotllán, Eva Royo Gelabert, Anna Rubio, Inmaculada Ruiz-Parrado, Shubha Sathyendranath, Jun She, Cosimo Solidoro, Emil V. Stanev, Joanna Staneva, Andrea Storto, Jian Su, Tayebeh Tajalli Bakhsh, Gavin H. Tilstone, Joaquín Tintoré, Cristina Toledano, Jean Tournadre, Benoit Tranchant, Rivo Uiboupin, Arnaud Valcarcel, Nadezhda Valcheva, Nathalie Verbrugge, Mathieu Vrac, J.-O. Wolff, Enrico Zambianchi, O. Zielinski, Ann-Sofie Zinck, Serena Zunino, Fundação para a Ciência e a Tecnologia (Portugal), Ministério da Ciência, Tecnologia e Ensino Superior (Portugal), Institut Cartogràfic i Geològic de Catalunya, 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), Universitat Politècnica de Catalunya. Laboratori d'Enginyeria Marítima, Universitat Politècnica de Catalunya. LIM/UPC - Laboratori d'Enginyeria Marítima, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), 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 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)-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), von Schuckmann K., Le Traon P.-Y., Smith N., Pascual A., Djavidnia S., Gattuso J.-P., Gregoire M., Nolan G., Aaboe S., Fanjul E.A., Aouf L., Aznar R., Badewien T.H., Behrens A., Berta M., Bertino L., Blackford J., Bolzon G., Borile F., Bretagnon M., Brewin R.J.W., Canu D., Cessi P., Ciavatta S., Chapron B., Trang Chau T.T., Chevallier F., Chtirkova B., Ciliberti S., Clark J.R., Clementi E., Combot C., Comerma E., Conchon A., Coppini G., Corgnati L., Cossarini G., Cravatte S., de Alfonso M., de Boyer Montegut C., De Lera Fernandez C., de los Santos F.J., Denvil-Sommer A., de Pascual Collar A., Dias Nunes P.A.L., Di Biagio V., Drudi M., Embury O., Falco P., d'Andon O.F., Ferrer L., Ford D., Freund H., Leon M.G., Sotillo M.G., Garcia-Valdecasas J.M., Garnesson P., Garric G., Gasparin F., Gehlen M., Genua-Olmedo A., Geyer G., Ghermandi A., Good S.A., Gourrion J., Greiner E., Griffa A., Gonzalez M., Hernandez-Carrasco I., Isoard S., Kennedy J.J., Kay S., Korosov A., Laanemae K., Land P.E., Lavergne T., Lazzari P., Legeais J.-F., Lemieux B., Levier B., Llovel W., Lyubartsev V., Lien V.S., Lima L., Lorente P., Mader J., Magaldi M.G., Mangin A., Maljutenko I., Mantovani C., Marinova V., Masina S., Mauri E., Meyerjurgens J., Mignot A., McEwan R., Mejia C., Melet A., Menna M., Meyssignac B., Mouche A., Mourre B., Muller M., Notarstefano G., Pardo S., Orfila A., Peneva E., Perez-Gomez B., Perruche C., Peterlin M., Poulain P.-M., Pinardi N., Quilfen Y., Raudsepp U., Renshaw R., Revelard A., Reyes-Reyes E., Ricker M., Rodriguez-Rubio P., Rotllan P., Gelabert E.R., Rubio A., Ruiz-Parrado I., Sathyendranath S., She J., Solidoro C., Stanev E.V., Staneva J., Storto A., Su J., Bakhsh T.T., Tilstone G.H., Tintore J., Toledano C., Tournadre J., Tranchant B., Uiboupin R., Valcarcel A., Valcheva N., Verbrugge N., Vrac M., Wolff J.-O., Zambianchi E., Zielinski O., and Zunino S.

Subjects
010504 meteorology & atmospheric sciences, media_common.quotation_subject, [SDE.MCG]Environmental Sciences/Global Changes, Public administration, Oceanography, 01 natural sciences, State (polity), Political science, 14. Life underwater, CMEMS, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Copernicus, media_common, Service (business), [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Enginyeria agroalimentària::Ciències de la terra i de la vida::Climatologia i meteorologia [Àrees temàtiques de la UPC], 010505 oceanography, Meteorologia marítima, Marine meteorology--Europe, [SDE.ES]Environmental Sciences/Environmental and Society, 13. Climate action, Enginyeria civil::Enginyeria hidràulica, marítima i sanitària::Ports i costes [Àrees temàtiques de la UPC], [SDE]Environmental Sciences, Ocean state report, Copernicus Marine Service, Environment policy
Abstract

Editors: Karina von Schuckmann; Pierre-Yves Le Traon.-- Review Editors: Neville Smith (Chair); Ananda Pascual; Samuel Djavidnia; Jean-Pierre Gattuso; Marilaure Grégoire; Glenn Nolan., The authors would like to thank the Institut Cartogràfic i Geològic de Catalunya (ICGC) for providing data. Thanks are due to FCT/MCTES for the financial support to CESAM (UID/AMB/50017/2019), through national funds., Chapter 1: Introduction and the European Environment policy framework.-- CMEMS OSR4, Chapter 2: State, variability and change in the ocean.-- CMEMS OSR4, Chapter 3: Case studies.-- CMEMS OSR4, Chapter 4: Specific events 2018.

Published
2020
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8. Copernicus Marine Service Ocean State Report, Issue 3

Author

Karina von Schuckmann, Pierre-Yves Le Traon, Neville Smith (Chair), Ananda Pascual, Samuel Djavidnia, Jean-Pierre Gattuso, Marilaure Grégoire, Glenn Nolan, Signe Aaboe, Enrique Álvarez Fanjul, Lotfi Aouf, Roland Aznar, T. H. Badewien, Arno Behrens, Maristella Berta, Laurent Bertino, Jeremy Blackford, Giorgio Bolzon, Federica Borile, Marine Bretagnon, Robert J.W. Brewin, Donata Canu, Paola Cessi, Stefano Ciavatta, Bertrand Chapron, Thi Tuyet Trang Chau, Frédéric Chevallier, Boriana Chtirkova, Stefania Ciliberti, James R. Clark, Emanuela Clementi, Clément Combot, Eric Comerma, Anna Conchon, Giovanni Coppini, Lorenzo Corgnati, Gianpiero Cossarini, Sophie Cravatte, Marta de Alfonso, Clément de Boyer Montégut, Christian De Lera Fernández, Francisco Javier de los Santos, Anna Denvil-Sommer, Álvaro de Pascual Collar, Paulo Alonso Lourenco Dias Nunes, Valeria Di Biagio, Massimiliano Drudi, Owen Embury, Pierpaolo Falco, Odile Fanton d'Andon, Luis Ferrer, David Ford, H. Freund, Manuel García León, Marcos García Sotillo, José María García-Valdecasas, Philippe Garnesson, Gilles Garric, Florent Gasparin, Marion Gehlen, Ana Genua-Olmedo, Gerhard Geyer, Andrea Ghermandi, Simon A. Good, Jérôme Gourrion, Eric Greiner, Annalisa Griffa, Manuel González, Ismael Hernández-Carrasco, Stéphane Isoard, John J. Kennedy, Susan Kay, Anton Korosov, Kaari Laanemäe, Peter E. Land, Thomas Lavergne, Paolo Lazzari, Jean-François Legeais, Benedicte Lemieux, Bruno Levier, William Llovel, Vladyslav Lyubartsev, Vidar S. Lien, Leonardo Lima, Pablo Lorente, Julien Mader, Marcello G. Magaldi, Ilja Maljutenko, Antoine Mangin, Carlo Mantovani, Veselka Marinova, Simona Masina, Elena Mauri, J. Meyerjürgens, Alexandre Mignot, Robert McEwan, Carlos Mejia, Angélique Melet, Milena Menna, Benoît Meyssignac, Alexis Mouche, Baptiste Mourre, Malte Müller, Giulio Notarstefano, Alejandro Orfila, Silvia Pardo, Elisaveta Peneva, Begoña Pérez-Gómez, Coralie Perruche, Monika Peterlin, Pierre-Marie Poulain, Nadia Pinardi, Yves Quilfen, Urmas Raudsepp, Richard Renshaw, Adèle Révelard, Emma Reyes-Reyes, M. Ricker, Pablo Rodríguez-Rubio, Paz Rotllán, Eva Royo Gelabert, Anna Rubio, Inmaculada Ruiz-Parrado, Shubha Sathyendranath, Jun She, Cosimo Solidoro, Emil V. Stanev, Joanna Staneva, Andrea Storto, Jian Su, Tayebeh Tajalli Bakhsh, Gavin H. Tilstone, Joaquín Tintoré, Cristina Toledano, Jean Tournadre, Benoit Tranchant, Rivo Uiboupin, Arnaud Valcarcel, Nadezhda Valcheva, Nathalie Verbrugge, Mathieu Vrac, J.-O. Wolff, Enrico Zambianchi, O. Zielinski, Ann-Sofie Zinck, Serena Zunino, Mercator Océan, Société Civile CNRS Ifremer IRD Météo-France SHOM, Laboratoire d’Oéanographie Spatiale [Plouzané] (LOS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire d'océanographie de Villefranche (LOV), 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), Norwegian Meteorological Institute, SOCIB Balearic Islands Coastal Ocean Observing and Forecasting System, Organismo publico puertos del estado, Université de Liège, Météo France, Met Office Climate Research Division, United Kingdom Met Office [Exeter], Helmholtz-Zentrum Geesthacht (GKSS), Royal Netherlands Meteorological Institute (KNMI), Institut National des Sciences et Techniques de la Mer (INSTM), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER), Consiglio Nazionale delle Ricerche (CNR), Istituto di Science Marine (ISMAR ), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Deltares system (NETHERLANDS), Deltares system, ARGANS, Consiglio Nazionale delle Ricerche [Napoli] (CNR), AZTI - Tecnalia, Nansen Environmental and Remote Sensing Center [Bergen] (NERSC), Universitat de Girona [Girona], Universitat de Girona (UdG), Centro Euro-Mediterraneo per i Cambiamenti Climatici [Bologna] (CMCC), Istituto di Scienze Marine [Napoli] (ISMAR-CNR), Consiglio Nazionale delle Ricerche (CNR)-Consiglio Nazionale delle Ricerche (CNR), Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Earth and Atmospheric Sciences [Atlanta], Georgia Institute of Technology [Atlanta], Parc Naturel Régional de Corse, Institut méditerranéen d'océanologie (MIO), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Processus et interactions de fine échelle océanique (PROTEO), Rijkswaterstaat [Delft], ACRI, acri, Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (ICM), Science et Technologie du Lait et de l'Oeuf (STLO), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Incheon National University, Alfred Wegener Institute [Potsdam], Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), University of Gothenburg (GU), Pacific Centre for Environment and Sustainable Development, University of the South Pacific (USP), Euro-Mediterranean Center on Climate Change (CMCC), Department of Biology, University of Zagreb, Hellenic Centre for Marine Research (HCMR), Laboratoire d'Acoustique de l'Université du Mans (LAUM), Centre National de la Recherche Scientifique (CNRS)-Le Mans Université (UM), Inst Ciencias Mar, Collecte Localisation Satellites (CLS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), Marine Ecosystems Modeling and Monitoring by Satellites (MEMMS), CLS, Departament d'Ecologia, Universitat de Barcelona (UB), Loughborough University, AZTI-Tecnalia (Marine Research Division), AZTI-Tecnalia, Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), Aarhus University [Aarhus], Departament d'Oceanografía Física, Institut de Ciències del Mar, Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), Sistema d’observació i predicció costaner de les Illes Balears (.) (SOCIB), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Universidad de las Islas Baleares (UIB), Institute of Biogeochemistry and Pollutant Dynamics [ETH Zürich] (IBP), Department of Environmental Systems Science [ETH Zürich] (D-USYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Processus de Transfert et d'Echanges dans l'Environnement - EA 3819 (PROTEE), Université de Toulon (UTLN), Plymouth Marine Laboratory (PML), Plymouth Marine Laboratory, Danish Meteorological Institute (DMI), Catalytic Spectroscopy Laboratory (CSIC), Institute of Catalysis and Petroleum Chemistry, Tallinn University of Technology (TalTech), Royal Belgian Institute of Natural Sciences (RBINS), Department of Animal Biology (Institute for Research on Biodiversity (IRBio)), University of Barcelona, Hellenic Center for Marine Research (HCMR), UMS 3343 (OSU), Observatoire des Sciences de l'Univers de Rennes (OSUR), European Centre for Medium-Range Weather Forecasts (ECMWF), 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), Norwegian Meteorological Institute [Oslo] (MET), Institut National des Sciences et Technologies de la Mer [Salammbô] (INSTM), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Deltares [The Netherlands], 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), 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), 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), Department of Biology [Zagreb], Faculty of Science [Zagreb], University of Zagreb-University of Zagreb, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), and Tallinn University of Technology (TTÜ)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, variability, HF radar, 010505 oceanography, Oceanography, 01 natural sciences, salinity, 12. Responsible consumption, 13. Climate action, Environmental science, 14. Life underwater, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The fundamental role of the ocean for life and well-being on Earth is more and more recognised at the highest political level. In 2015, the United Nations (UN) Sustainable Development Goals (SDGs) of the 2030 Agenda for Sustainable Development were adopted by world leaders. The SDG 14 ‘Conserve and sustainably use the oceans, seas and marine resources for sustainable development’ is dedicated to the oceans. The mention of the ocean in the Paris Agreement signed in 2016 marked a decisive milestone. In 2018, the UN Decade of Ocean Science for Sustainable Development (2021–2030) has been proclaimed (https://en.unesco.org/ocean-decade): The Intergovernmental Oceanographic Commission of UNESCO will gather ocean stakeholders worldwide behind a common framework to foster evidence-based policy-making. In fall 2019, the IPCC special report on ocean and cryosphere will be published, and will provide an opportunity to increase awareness and action before COP251 (already claimed as ‘Blue COP’).

Published
2019

9. A CMEMS forecasting system for the marine ecosystem of IBI European waters

Author

Alexandre Mignot, Tomasz Dabrowski, Marcos García Sotillo, Guillaume Reffray, and Elodie Gutknecht

Subjects
Current (stream), Mediterranean climate, Ocean dynamics, Biogeochemical cycle, Oceanography, Environmental science, Primary production, Biogeochemistry, Marine ecosystem, Satellite
Abstract

As part of the Copernicus Marine Environment Monitoring Service (CMEMS), an operational ocean forecasting system was developed to monitor the ocean dynamics and marine ecosystems of the European waters; and more specifically on the IBI (Iberia-Biscay-Ireland) area. The CMEMS IBI physical-biogeochemical coupled system covers the North-East Atlantic Ocean from the Canary Islands to Iceland, including the North Sea and the Western Mediterranean, with a NEMO-PISCES 1/36° model application. Since its operational launch in April 2018, this CMEMS IBI system has provided a weekly short-term (7-days) forecast of the ocean dynamics and key biogeochemical variables of the marine ecosystem. The main goal of this paper is to assess the performances of the IBI biogeochemical system, using a 7-year retrospective simulation that spans from 2010 to 2016. The model results are validated with available satellite and in situ observations from the International Council for the Exploration of the Sea (ICES), the European Marine Observation and Data Network (EMODnet) and the Biogeochemical-Argo float network. The simulation successfully reproduces the spatial distribution and seasonal cycles of oxygen, nutrients, chlorophyll-a, and net primary production. This simulation can be a useful tool to better understand the current state and changes in the marine biogeochemistry of European waters. It can also provide key variables for developing indicators to monitor the health of European marine ecosystems. These indicators may be of interest to scientists, policy makers, environmental agencies and the general public.

Published
2019

10. Seasonal dynamics and disturbance of phytoplankton biomass in the wake of Tahiti as observed by Biogeochemical-Argo floats

Author

Alexandre Mignot, Hervé Claustre, Keitapu Maamaatuaiahutapu, Julia Uitz, Christophe Maes, Raphaëlle Sauzède, Orens Pasqueron de Fommervault, Martine Rodier, Antoine Poteau, V. Laurent, Elodie Martinez, and Catherine Schmechtig

Subjects
0106 biological sciences, Biogeochemical cycle, Deep chlorophyll maximum, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Accumulation zone, Pelagic zone, 01 natural sciences, Water column, Oceanography, 13. Climate action, Ocean gyre, Phytoplankton, Environmental science, 14. Life underwater, Argo, 0105 earth and related environmental sciences
Abstract

The South Pacific Subtropical Gyre (SPSG) is a vast and remote area where large uncertainties on variability in phytoplankton biomass and production remain due to the lack of biogeochemical in situ observations. In such oligotrophic environments, ecosystems are predominantly controlled by nutrients depletion in surface waters. However, this oligotrophic character can be disturbed in the vicinity of islands where enhancement of biological activity is known to occur (i.e. the island mass effect, IME). This study mainly focuses on in situ observations showing that an IME can be evidenced leeward of Tahiti (17.7° S–149.5° W), French Polynesia. Concomitant physical and biogeochemical observations collected with two Biogeochemical-Argo (BGC-Argo) profiling floats from April 2015 to November 2016 are used to investigate the dynamics of phytoplankton biomass. The first float has a transit of more than 1000 km westward of Tahiti (open ocean conditions) while the second one remained in the Tahitian wake (around 45 km from the island coasts). In the oligotrophic central SPSG, the wintertime increase in upper layer chlorophyll a concentration is likely due to photoacclimation process. Vertical observations show a light-driven deepening of the deep chlorophyll maximum (DCM) from winter to summer, consistently with previous descriptions. At the opposite, within the Tahitian wake, the DCM temporary widens during late spring in association with a biological enhancement in the upper layer. Combining in situ measurements with meteorological data along the Tahiti coasts, Hybrid Coordinate Ocean Model outputs and satellite-derived products (i.e., horizontal currents and associated fronts), the physical mechanisms involved in the disturbance of phytoplankton seasonal cycle in the Tahitian wake have been investigated. This disturbance results from the concomitant occurrence of strong precipitations and a zone of weak currents leeward Tahiti. We conjecture that the land drainage induces a significant supply of nitrate in the ocean upper layer (down to ~ 100 m) while a zone of weak currents in the southwestern zone behind Tahiti forms an accumulation zone, hence allowing phytoplankton growth up to 20 km away from the coastlines. Moreover, bio-optical measurements suggest that the composition of phytoplankton community could differ in the Tahitian wake vs. the open ocean area. Finally, in addition to extending information to the water column, only BGC-Argo floats could provide biogeochemical measurements in the SPSG region when clouds prevent the use of remote sensing.

Published
2018

11. Retrieving the vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: A method based on a neural network with potential for global-scale applications

Author

Julia Uitz, Cédric Jamet, Alexandre Mignot, Fabrizio D'Ortenzio, Hervé Claustre, Josephine Ras, 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), Collecte Localisation Satellites (CLS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), 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 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, In situ, Bermuda Atlantic Time-series Study, Chlorophyll a, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Oceanography, 01 natural sciences, Fluorescence, chemistry.chemical_compound, Geophysics, chemistry, Space and Planetary Science, Geochemistry and Petrology, Nanophytoplankton, Phytoplankton, Earth and Planetary Sciences (miscellaneous), Environmental science, 14. Life underwater, Scale (map), Chlorophyll fluorescence, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Remote sensing
Abstract

International audience; A neural network-based method is developed to assess the vertical distribution of (1) chlorophyll a concentration ([Chl]) and (2) phytoplankton community size indices (i.e., microphytoplankton, nanophytoplankton, and picophytoplankton) from in situ vertical profiles of chlorophyll fluorescence. This method (FLAVOR for Fluorescence to Algal communities Vertical distribution in the Oceanic Realm) uses as input only the shape of the fluorescence profile associated with its acquisition date and geo-location. The neural network is trained and validated using a large database including 896 concomitant in situ vertical profiles of High-Performance Liquid Chromatography (HPLC) pigments and fluorescence. These profiles were collected during 22 oceanographic cruises representative of the global ocean in terms of trophic and oceanographic conditions, making our method applicable to most oceanic waters. FLAVOR is validated with respect to the retrieval of both [Chl] and phytoplankton size indices using an independent in situ data set and appears to be relatively robust spatially and temporally. To illustrate the potential of the method, we applied it to in situ measurements of the BATS (Bermuda Atlantic Time Series Study) site and produce monthly climatologies of [Chl] and associated phytoplankton size indices. The resulting climatologies appear very promising compared to climatologies based on available in situ HPLC data. With the increasing availability of spatially and temporally well-resolved data sets of chlorophyll fluorescence, one possible global-scale application of FLAVOR could be to develop 3-D and even 4-D climatologies of [Chl] and associated composition of phytoplankton communities. The Matlab and R codes of the proposed algorithm are provided as supporting information.

Published
2015

12. Spring bloom onset in the Nordic Seas

Author

Kjell Arne Mork, Alexandre Mignot, Raffaele Ferrari, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Mignot, Alexandre, and Ferrari, Raffaele

Subjects
0106 biological sciences, VDP::Matematikk og naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488, 010504 meteorology & atmospheric sciences, lcsh:Life, Irradiance, 01 natural sciences, Latitude, Algae, lcsh:QH540-549.5, Phytoplankton, Spring (hydrology), 14. Life underwater, Ecology, Evolution, Behavior and Systematics, Earth-Surface Processes, 0105 earth and related environmental sciences, Biomass (ecology), geography, geography.geographical_feature_category, VDP::Mathematics and natural scienses: 400::Zoology and botany: 480::Ecology: 488, biology, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, fungi, Spring bloom, biology.organism_classification, Food web, lcsh:Geology, lcsh:QH501-531, Oceanography, lcsh:Ecology
Abstract

The North Atlantic spring bloom is a massive annual growth event of marine phytoplankton, tiny free-floating algae that form the base of the ocean's food web and generates a large fraction of the global primary production of organic matter. The conditions that trigger the onset of the spring bloom in the Nordic Seas, at the northern edge of the North Atlantic, are studied using in situ data from six bio-optical floats released north of the Arctic Circle. It is often assumed that spring blooms start as soon as phytoplankton cells daily irradiance is sufficiently abundant that division rates exceed losses. The bio-optical float data instead suggest the tantalizing hypothesis that Nordic Seas blooms start when the photoperiod, the number of daily light hours experienced by phytoplankton, exceeds a critical value, independently of division rates. The photoperiod trigger may have developed at high latitudes where photosynthesis is impossible during polar nights and phytoplankton enters into a dormant stage in winter. While the first accumulation of biomass recorded by the bio-optical floats is consistent with the photoperiod hypothesis, it is possible that some biomass accumulation started before the critical photoperiod but at levels too low to be detected by the fluorometers. More precise observations are needed to test the photoperiod hypothesis., National Science Foundation (U.S.) (NSF award OCE-1155205)

Published
2015

13. 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

14. 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

15. A new estimate of the global 3D geostrophic ocean circulation based on satellite data and in-situ measurements

Author

Sandrine Mulet, Rosemary Morrow, Marie-Hélène Rio, Stephanie Guinehut, Alexandre Mignot, Collecte Localisation Satellites (CLS), Centre National d'Études Spatiales [Toulouse] (CNES)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Océan du Large et Variabilité Climatique (OLVAC), 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), 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
0106 biological sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010504 meteorology & atmospheric sciences, 010604 marine biology & hydrobiology, Ocean current, Temperature salinity diagrams, Thermal wind, Oceanography, 01 natural sciences, Current meter, Amplitude, 13. Climate action, Climatology, 14. Life underwater, Altimeter, Geology, Argo, Geostrophic wind, 0105 earth and related environmental sciences
Abstract

International audience; A new estimate of the Global Ocean 3D geostrophic circulation from the surface down to 1500 m depth (Surcouf3D) has been computed for the 1993-2008 period using an observation-based approach that combines altimetry with temperature and salinity through the thermal wind equation. The validity of this simple approach was tested using a consistent dataset from a model reanalysis. Away from the boundary layers, errors are less than 10% in most places, which indicate that the thermal wind equation is a robust approximation to reconstruct the 3D oceanic circulation in the ocean interior. The Surcouf3D current field was validated in the Atlantic Ocean against in-situ observations. We considered the ANDRO current velocities deduced at 1000 m depth from Argo float displacements as well as velocity measurements at 26.5°N from the RAPID-MOCHA current meter array. The Surcouf3D currents show similar skill to the 3D velocities from the GLORYS Mercator Ocean reanalysis in reproducing the amplitude and variability of the ANDRO currents. In the upper 1000 m, high correlations are also found with in-situ velocities measured by the RAPID-MOCHA current meters. The Surcouf3D current field was then used to compute estimates of the Atlantic Meridional Overturning Circulation (AMOC) through the 25°N section, showing good comparisons with hydrographic sections from 1998 and 2004. Monthly averaged AMOC time series are also consistent with the RAPID-MOCHA array and with the GLORYS Mercator Ocean reanalysis over the April 2004-September 2007 period. Finally a 15 years long time series of monthly estimates of the AMOC was computed. The AMOC strength has a mean value of 16 Sv with an annual (resp. monthly) standard deviation of 2.4 Sv (resp. 7.1 Sv) over the 1993-2008 period. The time series, characterized by a strong variability, shows no significant trend.

Published
2012

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