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4. The GEOTRACES Intermediate Data Product 2017

Author

Schlitzer, Reiner, Anderson, Robert F., Dodas, Elena Masferrer, Lohan, Maeve, Geibert, Walter, Tagliabue, Alessandro, Bowie, Andrew, Jeandel, Catherine, Maldonado, Maria T., Landing, William M., Cockwell, Donna, Abadie, Cyril, Abouchami, Wafa, Achterberg, Eric P., Agather, Alison, Aguliar-Islas, Ana, van Aken, Hendrik M., Andersen, Morten, Archer, Corey, Auro, Maureen, de Baar, Hein J., Baars, Oliver, Baker, Alex R., Bakker, Karel, Basak, Chandranath, Baskaran, Mark, Bates, Nicholas R., Bauch, Dorothea, van Beek, Pieter, Behrens, Melanie K., Black, Erin, Bluhm, Katrin, Bopp, Laurent, Bouman, Heather, Bowman, Katlin, Bown, Johann, Boyd, Philip, Boye, Marie, Boyle, Edward A., Branellec, Pierre, Bridgestock, Luke, Brissebrat, Guillaume, Browning, Thomas, Bruland, Kenneth W., Brumsack, Hans-Jürgen, Brzezinski, Mark, Buck, Clifton S., Buck, Kristen N., Buesseler, Ken, Bull, Abby, Butler, Edward, Cai, Pinghe, Mor, Patricia Cámara, Cardinal, Damien, Carlson, Craig, Carrasco, Gonzalo, Casacuberta, Núria, Casciotti, Karen L., Castrillejo, Maxi, Chamizo, Elena, Chance, Rosie, Charette, Matthew A., Chaves, Joaquin E., Cheng, Hai, Chever, Fanny, Christl, Marcus, Church, Thomas M., Closset, Ivia, Colman, Albert, Conway, Tim M., Cossa, Daniel, Croot, Peter, Cullen, Jay T., Cutter, Gregory A., Daniels, Chris, Dehairs, Frank, Deng, Feifei, Dieu, Huong Thi, Duggan, Brian, Dulaquais, Gabriel, Dumousseaud, Cynthia, Echegoyen-Sanz, Yolanda, Edwards, R. Lawrence, Ellwood, Michael, Fahrbach, Eberhard, Fitzsimmons, Jessica N., Russell Flegal, A., Fleisher, Martin Q., van de Flierdt, Tina, Frank, Martin, Friedrich, Jana, Fripiat, Francois, Fröllje, Henning, Galer, Stephen J.G., Gamo, Toshitaka, Ganeshram, Raja S., Garcia-Orellana, Jordi, Garcia-Solsona, Ester, Gault-Ringold, Melanie, George, Ejin, Gerringa, Loes J.A., Gilbert, Melissa, Godoy, Jose M., Goldstein, Steven L., Gonzalez, Santiago R., Grissom, Karen, Hammerschmidt, Chad, Hartman, Alison, Hassler, Christel S., Hathorne, Ed C., Hatta, Mariko, Hawco, Nicholas, Hayes, Christopher T., Heimbürger, Lars-Eric, Helgoe, Josh, Heller, Maija, Henderson, Gideon M., Henderson, Paul B., van Heuven, Steven, Ho, Peng, Horner, Tristan J., Hsieh, Yu-Te, Huang, Kuo-Fang, Humphreys, Matthew P., Isshiki, Kenji, Jacquot, Jeremy E., Janssen, David J., Jenkins, William J., John, Seth, Jones, Elizabeth M., Jones, Janice L., Kadko, David C., Kayser, Rick, Kenna, Timothy C., Khondoker, Roulin, Kim, Taejin, Kipp, Lauren, Klar, Jessica K., Klunder, Maarten, Kretschmer, Sven, Kumamoto, Yuichiro, Laan, Patrick, Labatut, Marie, Lacan, Francois, Lam, Phoebe J., Lambelet, Myriam, Lamborg, Carl H., Le Moigne, Frédéric A.C., Le Roy, Emilie, Lechtenfeld, Oliver J., Lee, Jong-Mi, Lherminier, Pascale, Little, Susan, López-Lora, Mercedes, Lu, Yanbin, Masque, Pere, Mawji, Edward, Mcclain, Charles R., Measures, Christopher, Mehic, Sanjin, Barraqueta, Jan-Lukas Menzel, van der Merwe, Pier, Middag, Rob, Mieruch, Sebastian, Milne, Angela, Minami, Tomoharu, Moffett, James W., Moncoiffe, Gwenaelle, Moore, Willard S., Morris, Paul J., Morton, Peter L., Nakaguchi, Yuzuru, Nakayama, Noriko, Niedermiller, John, Nishioka, Jun, Nishiuchi, Akira, Noble, Abigail, Obata, Hajime, Ober, Sven, Ohnemus, Daniel C., van Ooijen, Jan, O'Sullivan, Jeanette, Owens, Stephanie, Pahnke, Katharina, Paul, Maxence, Pavia, Frank, Pena, Leopoldo D., Peters, Brian, Planchon, Frederic, Planquette, Helene, Pradoux, Catherine, Puigcorbé, Viena, Quay, Paul, Queroue, Fabien, Radic, Amandine, Rauschenberg, S., Rehkämper, Mark, Rember, Robert, Remenyi, Tomas, Resing, Joseph A., Rickli, Joerg, Rigaud, Sylvain, Rijkenberg, Micha J.A., Rintoul, Stephen, Robinson, Laura F., Roca-Martí, Montserrat, Rodellas, Valenti, Roeske, Tobias, Rolison, John M., Rosenberg, Mark, Roshan, Saeed, Rutgers van der Loeff, Michiel M., Ryabenko, Evgenia, Saito, Mak A., Salt, Lesley A., Sanial, Virginie, Sarthou, Geraldine, Schallenberg, Christina, Schauer, Ursula, Scher, Howie, Schlosser, Christian, Schnetger, Bernhard, Scott, Peter, Sedwick, Peter N., Semiletov, Igor, Shelley, Rachel, Sherrell, Robert M., Shiller, Alan M., Sigman, Daniel M., Singh, Sunil Kumar, Slagter, Hans A., Slater, Emma, Smethie, William M., Snaith, Helen, Sohrin, Yoshiki, Sohst, Bettina, Sonke, Jeroen E., Speich, Sabrina, Steinfeldt, Reiner, Stewart, Gillian, Stichel, Torben, Stirling, Claudine H., Stutsman, Johnny, Swarr, Gretchen J., Swift, James H., Thomas, Alexander, Thorne, Kay, Till, Claire P., Till, Ralph, Townsend, Ashley T., Townsend, Emily, Tuerena, Robyn, Twining, Benjamin S., Vance, Derek, Velazquez, Sue, Venchiarutti, Celia, Villa-Alfageme, Maria, Vivancos, Sebastian M., Voelker, Antje H.L., Wake, Bronwyn, Warner, Mark J., Watson, Ros, van Weerlee, Evaline, Alexandra Weigand, M., Weinstein, Yishai, Weiss, Dominik, Wisotzki, Andreas, Woodward, E. Malcolm S., Wu, Jingfeng, Wu, Yingzhe, Wuttig, Kathrin, Wyatt, Neil, Xiang, Yang, Xie, Ruifang C., Xue, Zichen, Yoshikawa, Hisayuki, Zhang, Jing, Zhang, Pu, Zhao, Ye, Zheng, Linjie, Zheng, Xin-Yuan, Zieringer, Moritz, Zimmer, Louise A., Ziveri, Patrizia, Zunino, Patricia, and Zurbrick, Cheryl

Published
2018
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5. Concepts Toward a Global Mechanistic Mapping of Ocean Carbon Export

Author

Laurenceau-cornec, Emmanuel C., Mongin, Mathieu, Trull, Thoams W., Bressac, Matthieu, Cavan, Emma L., Bach, Lennart T., Le Moigne, Frédéric A.c., Planchon, Frédéric, Boyd, Philip W., Laurenceau-cornec, Emmanuel C., Mongin, Mathieu, Trull, Thoams W., Bressac, Matthieu, Cavan, Emma L., Bach, Lennart T., Le Moigne, Frédéric A.c., Planchon, Frédéric, and Boyd, Philip W.

Abstract

The gravitational sinking of organic debris from ocean ecosystems is a dominant mechanism of the biological carbon pump (BCP) that regulates global climate. The fraction of primary production exported downward, the e-ratio, is an important but poorly constrained BCP metric. In mid- and high-latitude oceans, seasonal and local variations of sinking particle fluxes modulate strongly the e-ratio. These locally-specific e-ratio variations and their ecological foundations are here encapsulated in the term ‘export systems’ (ES). ES have been partly characterized for a few ocean locations, but remain largely ignored over most of ocean's surface. Here, in a fully conceptual approach and with the primary aim to understand rather than to estimate ocean carbon export, we combine biogeochemical (BGC) modeling with satellite observations to map ES at fine spatio-temporal scales. We identify four plausible ES with distinct e-ratio seasonalities across mid- and high-latitude oceans. The ES map confirms the outlines of traditional BGC provinces, and unveils new boundaries indicating where (and how) the annual relationship between carbon export and production changes markedly. At six sites where ES features can be partially inferred from in situ data, we test our approach and propose key ecological processes driving carbon export. In the light of our findings, a re-examination of 1,841 field-based e-ratios could challenge the conventional wisdom that e-ratios change strongly with latitude, suggesting a possible seasonal artefact caused by the timing of observations. By deciphering carbon export mechanistically, our conceptual ES map gives timely directions to emergent ocean robotic explorations of the BCP. Key Points A plausible mechanistic map of ocean carbon export is derived from spatio-temporal changes of the e-ratio in mid and high-latitude oceans The map unveils the possible distribution and boundaries of four main systems of export and explains their potential ecological driv

Published
2023
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10. Seasonal microbial food web dynamics in contrasting Southern Ocean productivity regimes

Author

Chistaki, Urania, Guenegues, Audrey, Liu, Yan, Blain, Stéphane, Catala, Philippe, Colombet, Jonathan, Debeljak, Pavla, Jardillier, Ludwig, Irion, Solène, Planchon, Frédéric, Sassenhagen, Ingrid, Sime-Ngando, Télesphore, Obernosterer, Ingrid, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-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), Laboratoire Microorganismes : Génome et Environnement - Clermont Auvergne (LMGE), Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Ecologie Systématique et Evolution (ESE), Centre National de la Recherche Scientifique (CNRS)-AgroParisTech-Université Paris-Sud - Paris 11 (UP11), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE01-0013,MOBYDICK,Biodiversité des Ecosystèmes Marins et Dynamique du Carbone dans le secteur de Kerguelen : approche intégrée(2017), 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 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 du Littoral Côte d'Opale (ULCO), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), AgroParisTech-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)-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), We thank B. Queguiner, the PI of the MOBYDICK project, for providing us the opportunity to participate to this cruise, the captain and crew of the R/V Marion Dufresne for their enthusiasm and support aboard during the MOBYDICK-THEMISTO cruise (https://doi.org/10.17600/18000403) and the chief scientist I. Obernosterer. This work was supported by the French oceanographic fleet ('Flotte oceanographique francaise'), the French ANR ('Agence Nationale de la Recherche', AAPG 2017 program, MOBYDICK Project number: ANR-17-CE01-0013), and the French Research program of INSU-CNRS LEFE/CYBER ('Les enveloppes fluides et l'environnement'-'Cycles biogeochimiques, environnement et ressources'). This work was also supported by ULCO (Universite du Littoral) and CPER MARCO (https://marco.univ-littoral.fr/).We thank three anonymous reviewers and the editors for their comments which helped to improve this work., 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), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire Européen de la Mer (IUEM), and 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)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ekologi, kerguelen area, Ecology, ACL, chibido, marine, phytoplankton bloom, Microbial food web, fluxes, natural iron fertilization, viral-infection, inverse relationship, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, carbon export, productivity regimes, export efficiency, community structure, crozet plateau, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Southern Ocean, UBO, ANR-17-CE01-0013, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience; Spatial and seasonal dynamics of microbial loop fluxes were investigated in contrasting productivity regimes in the Indian sector of the Southern Ocean. Observations carried out in late summer (February-March 2018; project MOBYDICK) revealed higher microbial biomasses and fluxes in the naturally iron-fertilized surface waters of Kerguelen island in comparison to surrounding off-plateau waters. Differences were most pronounced for bacterial heterotrophic production (2.3-fold), the abundance of heterotrophic nanoflagellates (HNF; 2.7-fold). Independent of site, grazing by HNF was the main loss process of bacterial production (80-100%), while virus-induced mortality was low (\textless 9%). Combining these results with observations from previous investigations during early spring and summer allowed us to describe seasonal patterns in microbial food web fluxes and to compare these to carbon export in the iron-fertilized and high-nutrient, low-chlorophyll (HNLC) Southern Ocean. Our data suggest an overall less efficient microbial food web during spring and summer, when respiration and viral lysis, respectively, represent important loss terms of bacterially-mediated carbon. In late summer, primary production is more efficiently transferred to bacterial biomass and HNF and thus available for higher trophic levels. These results provide a new insight into the seasonal variability and the quantitative importance of microbial food web processes for the fate of primary production in the Southern Ocean.

Published
2020

11. Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise

Author

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Sarthou, Géraldine, Lherminier, Pascale, Achterberg, Eric P., Alonso-Pérez, Fernando, Bucciarelli, Eva, Boutorh, Julia, Bouvier, Vincent, Boyle, Edward A, Branellec, Pierre, Carracedo, Lidia I., Casacuberta, Nuria, Castrillejo, Maxi, Cheize, Marie, Contreira Pereira, Leonardo, Cossa, Daniel, Daniault, Nathalie, De Saint-Léger, Emmanuel, Dehairs, Frank, Deng, Feifei, Desprez de Gésincourt, Floriane, Devesa, Jérémy, Foliot, Lorna, Fonseca-Batista, Debany, Gallinari, Morgane, García-Ibáñez, Maribel I., Gourain, Arthur, Grossteffan, Emilie, Hamon, Michel, Heimbürger, Lars Eric, Henderson, Gideon M., Jeandel, Catherine, Kermabon, Catherine, Lacan, François, Le Bot, Philippe, Le Goff, Manon, Le Roy, Emilie, Lefèbvre, Alison, Leizour, Stéphane, Lemaitre, Nolwenn, Masqué, Pere, Ménage, Olivier, Menzel Barraqueta, Jan-Lukas, Mercier, Herlé, Perault, Fabien, Pérez, Fiz F., Planquette, Hélène F., Planchon, Frédéric, Roukaerts, Arnout, Sanial, Virginie, Sauzède, Raphaëlle, Schmechtig, Catherine, Shelley, Rachel U., Stewart, Gillian, Sutton, Jill N., Tang, Yi, Tisnérat-Laborde, Nadine, Tonnard, Manon, Tréguer, Paul, van Beek, Pieter, Zurbrick, Cheryl M, Zunino, Patricia, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Sarthou, Géraldine, Lherminier, Pascale, Achterberg, Eric P., Alonso-Pérez, Fernando, Bucciarelli, Eva, Boutorh, Julia, Bouvier, Vincent, Boyle, Edward A, Branellec, Pierre, Carracedo, Lidia I., Casacuberta, Nuria, Castrillejo, Maxi, Cheize, Marie, Contreira Pereira, Leonardo, Cossa, Daniel, Daniault, Nathalie, De Saint-Léger, Emmanuel, Dehairs, Frank, Deng, Feifei, Desprez de Gésincourt, Floriane, Devesa, Jérémy, Foliot, Lorna, Fonseca-Batista, Debany, Gallinari, Morgane, García-Ibáñez, Maribel I., Gourain, Arthur, Grossteffan, Emilie, Hamon, Michel, Heimbürger, Lars Eric, Henderson, Gideon M., Jeandel, Catherine, Kermabon, Catherine, Lacan, François, Le Bot, Philippe, Le Goff, Manon, Le Roy, Emilie, Lefèbvre, Alison, Leizour, Stéphane, Lemaitre, Nolwenn, Masqué, Pere, Ménage, Olivier, Menzel Barraqueta, Jan-Lukas, Mercier, Herlé, Perault, Fabien, Pérez, Fiz F., Planquette, Hélène F., Planchon, Frédéric, Roukaerts, Arnout, Sanial, Virginie, Sauzède, Raphaëlle, Schmechtig, Catherine, Shelley, Rachel U., Stewart, Gillian, Sutton, Jill N., Tang, Yi, Tisnérat-Laborde, Nadine, Tonnard, Manon, Tréguer, Paul, van Beek, Pieter, Zurbrick, Cheryl M, and Zunino, Patricia

Abstract

The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special-issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.

Published
2020

14. Study of Synthesis Pathways of the Essential Polyunsaturated Fatty Acid 20:5n-3 in the Diatom Chaetoceros Muelleri Using 13C-Isotope Labeling

Author

Remize, Marine, primary, Planchon, Frédéric, additional, Loh, Ai Ning, additional, Le Grand, Fabienne, additional, Bideau, Antoine, additional, Le Goic, Nelly, additional, Fleury, Elodie, additional, Miner, Philippe, additional, Corvaisier, Rudolph, additional, Volety, Aswani, additional, and Soudant, Philippe, additional

Published
2020
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15. Evidence of high N2 fixation rates in the temperate northeast Atlantic

Author

Fonseca-Batista, Debany, Li, Xuefeng, Riou, Virginie, Michotey, Valerie, Deman, Florian, Fripiat, François, Guasco, Sophie, Brion, Natacha, Lemaitre, Nolwenn, Tonnard, Manon, Gallinari, Morgane, Planquette, Hélène, Planchon, Frédéric, Sarthou, Géraldine, Elskens, Marc, Laroche, Julie, Chou, Lei, Dehairs, Frank, Vrije Universiteit [Brussels] (VUB), Key Laboratory of Bio-resources and Eco-environment, ministry of education-College of Life Sciences-Sichuan University, Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de MicrobiologiE de Géochimie et d'Ecologie Marines (LMGEM), Université de la Méditerranée - Aix-Marseille 2-Centre National de la Recherche Scientifique (CNRS), Analytical, Environmental and Geo- Chemistry, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Analytical and Environmental Chemistry and Earth System Sciences, ANR-13-BS06-0014,GEOVIDE,GEOVIDE, Une étude internationale GEOTRACES le long de la section OVIDE en Atlantique Nord et en Mer du Labrador(2013), ANR: 11-LABX-0061,Labex OT- Med,ANR-11-LABEX-0061, ANR-11-IDEX-0001-02/11-IDEX-0001,AMIDEX,AMIDEX(2011), Vrije Universiteit Brussel (VUB), Dalhousie University [Halifax], Université libre de Bruxelles (ULB), 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), Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, 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), Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institute for Marine and Antarctic Studies [Hobart] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), ANR-11-LABX-0061,OTMed,Objectif Terre : Bassin Méditerranéen(2011), ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011), Centre National de la Recherche Scientifique (CNRS)-Université de la Méditerranée - Aix-Marseille 2, Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institute for Marine and Antarctic Studies [Horbat] (IMAS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ecologie, Géologie et minéralogie, IRON, ACL, [SDE.MCG]Environmental Sciences/Global Changes, ENVIRONMENTAL CONTROLS, Evolution des espèces, VARIABILITY, NIFH GENES, DIAZOTROPHIC CYANOBACTERIA, TRICHODESMIUM, [SDE]Environmental Sciences, DINITROGEN-FIXATION, DISTRIBUTIONS, NITROGEN-FIXATION, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, MARINE
Abstract

Diazotrophic activity and primary production (PP) were investigated along two transects (Belgica BG2014/14 and GEOVIDE cruises) off the western Iberian Margin and the Bay of Biscay in May 2014. Substantial N 2 fixation activity was observed at 8 of the 10 stations sampled, ranging overall from 81 to 384 μmolNm -2 d -1 (0.7 to 8.2 nmolNL -1 d -1 ,with two sites close to the Iberian Margin situated between 38.8 and 40.7° N yielding rates reaching up to 1355 and 1533 μmolNm -2 d -1 .Primary production was relatively lower along the Iberian Margin, with rates ranging from 33 to 59 mmol Cm -2 d -1 ,while it increased towards the northwest away from the peninsula, reaching as high as 135 mmol Cm -2 d -1 .In agreement with the area-averaged Chl a satellite data contemporaneous with our study period, our results revealed that post-bloom conditions prevailed at most sites, while at the northwesternmost station the bloom was still ongoing. When converted to carbon uptake using Redfield stoichiometry, N 2 fixation could support 1% to 3% of daily PP in the euphotic layer at most sites, except at the two most active sites where this contribution to daily PP could reach up to 25 %. At the two sites where N 2 fixation activity was the highest, the prymnesiophyte.symbiont Candidatus Atelocyanobacterium thalassa (UCYN-A) dominated the nifH sequence pool, while the remaining recovered sequences belonged to non-cyanobacterial phylotypes. At all the other sites, however, the recovered nifH sequences were exclusively assigned phylogenetically to non-cyanobacterial phylotypes. The intense N 2 fixation activities recorded at the time of our study were likely promoted by the availability of phytoplanktonderived organic matter produced during the spring bloom, as evidenced by the significant surface particulate organic carbon concentrations. Also, the presence of excess phosphorus signature in surface waters seemed to contribute to sustaining N 2 fixation, particularly at the sites with extreme activities. These results provide a mechanistic understanding of the unexpectedly high N 2 fixation in productive waters of the temperate North Atlantic and highlight the importance of N 2 fixation for future assessment of the global N inventory., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2019

17. Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise

Author

Sarthou, Géraldine, primary, Lherminier, Pascale, additional, Achterberg, Eric P., additional, Alonso-Pérez, Fernando, additional, Bucciarelli, Eva, additional, Boutorh, Julia, additional, Bouvier, Vincent, additional, Boyle, Edward A., additional, Branellec, Pierre, additional, Carracedo, Lidia I., additional, Casacuberta, Nuria, additional, Castrillejo, Maxi, additional, Cheize, Marie, additional, Contreira Pereira, Leonardo, additional, Cossa, Daniel, additional, Daniault, Nathalie, additional, De Saint-Léger, Emmanuel, additional, Dehairs, Frank, additional, Deng, Feifei, additional, Desprez de Gésincourt, Floriane, additional, Devesa, Jérémy, additional, Foliot, Lorna, additional, Fonseca-Batista, Debany, additional, Gallinari, Morgane, additional, García-Ibáñez, Maribel I., additional, Gourain, Arthur, additional, Grossteffan, Emilie, additional, Hamon, Michel, additional, Heimbürger, Lars Eric, additional, Henderson, Gideon M., additional, Jeandel, Catherine, additional, Kermabon, Catherine, additional, Lacan, François, additional, Le Bot, Philippe, additional, Le Goff, Manon, additional, Le Roy, Emilie, additional, Lefèbvre, Alison, additional, Leizour, Stéphane, additional, Lemaitre, Nolwenn, additional, Masqué, Pere, additional, Ménage, Olivier, additional, Menzel Barraqueta, Jan-Lukas, additional, Mercier, Herlé, additional, Perault, Fabien, additional, Pérez, Fiz F., additional, Planquette, Hélène F., additional, Planchon, Frédéric, additional, Roukaerts, Arnout, additional, Sanial, Virginie, additional, Sauzède, Raphaëlle, additional, Schmechtig, Catherine, additional, Shelley, Rachel U., additional, Stewart, Gillian, additional, Sutton, Jill N., additional, Tang, Yi, additional, Tisnérat-Laborde, Nadine, additional, Tonnard, Manon, additional, Tréguer, Paul, additional, van Beek, Pieter, additional, Zurbrick, Cheryl M., additional, and Zunino, Patricia, additional

Published
2018
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18. High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from <sup>234</sup>Th fluxes

Author

Lemaitre, Nolwenn, primary, Planchon, Frédéric, additional, Planquette, Hélène, additional, Dehairs, Frank, additional, Fonseca-Batista, Debany, additional, Roukaerts, Arnout, additional, Deman, Florian, additional, Tang, Yi, additional, Mariez, Clarisse, additional, and Sarthou, Géraldine, additional

Published
2018
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20. Introduction to the French GEOTRACES North Atlantic transect (GA01): GEOVIDE cruise

Author

Sarthou, Geraldine, Lherminier, Pascale, Achterberg, Eric P., Alonso-Pérez, Fernando, Bucciarelli, Eva, Boutorh, Julia, Bouvier, Vincent, Boyle, Edward A., Branellec, Pierre, Carracedo, Lidia I., Casacuberta, Nuria, Castrillejo, Maxi, Cheize, Marie, Contreira Pereira, Leonardo, Cossa, Daniel, Daniault, Nathalie, De Saint-Léger, Emmanuel, Dehairs, Frank, Deng, Feifei, Desprez de Gésincourt, Floriane, Devesa, Jérémy, Foliot, Lorna, Fonseca-Batista, Debany, Gallinari, Morgane, García-Ibáñez, Maribel I., Gourain, Arthur, Grossteffan, Emilie, Hamon, Michel, Heimbürger, Lars Eric, Henderson, Gideon M., Jeandel, Catherine, Kermabon, Catherine, Lacan, François, Le Bot, Phillippe, Le Goff, Manon, Le Roy, Emilie, Lefèbvre, Alison, Leizour, Stéphane, Lemaitre, Nolwenn, Masqué, Pere, Ménage, Olivier, Barraqueta, Jan-Lukas Menzel, Mercier, Herlé, Perault, Fabien, Pérez, Fiz F., Planquette, Hélène F., Planchon, Frédéric, Roukaerts, Arnout, Sanial, Virginie, Sauzède, Raphaëlle, Schmechtig, Catherine, Shelley, Rachel U., Stewart, Gillian, Sutton, Jill N., Tang, Yi, Tisnérat-Laborde, Nadine, Tonnard, Manon, Tréguer, Paul, van Beek, Pieter, Zurbrick, Cheryl M., Zunino, Patricia, Sarthou, Geraldine, Lherminier, Pascale, Achterberg, Eric P., Alonso-Pérez, Fernando, Bucciarelli, Eva, Boutorh, Julia, Bouvier, Vincent, Boyle, Edward A., Branellec, Pierre, Carracedo, Lidia I., Casacuberta, Nuria, Castrillejo, Maxi, Cheize, Marie, Contreira Pereira, Leonardo, Cossa, Daniel, Daniault, Nathalie, De Saint-Léger, Emmanuel, Dehairs, Frank, Deng, Feifei, Desprez de Gésincourt, Floriane, Devesa, Jérémy, Foliot, Lorna, Fonseca-Batista, Debany, Gallinari, Morgane, García-Ibáñez, Maribel I., Gourain, Arthur, Grossteffan, Emilie, Hamon, Michel, Heimbürger, Lars Eric, Henderson, Gideon M., Jeandel, Catherine, Kermabon, Catherine, Lacan, François, Le Bot, Phillippe, Le Goff, Manon, Le Roy, Emilie, Lefèbvre, Alison, Leizour, Stéphane, Lemaitre, Nolwenn, Masqué, Pere, Ménage, Olivier, Barraqueta, Jan-Lukas Menzel, Mercier, Herlé, Perault, Fabien, Pérez, Fiz F., Planquette, Hélène F., Planchon, Frédéric, Roukaerts, Arnout, Sanial, Virginie, Sauzède, Raphaëlle, Schmechtig, Catherine, Shelley, Rachel U., Stewart, Gillian, Sutton, Jill N., Tang, Yi, Tisnérat-Laborde, Nadine, Tonnard, Manon, Tréguer, Paul, van Beek, Pieter, Zurbrick, Cheryl M., and Zunino, Patricia

Abstract

The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.

Published
2018

21. Introduction to the French GEOTRACES North Atlantic transect (GA01): GEOVIDE cruise

Author

LabexMER, Institut Français de Recherche pour l'Exploitation de la Mer, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Sarthou, Géraldine, Lherminier, Pascale, Achterberg, Eric P., Alonso Pérez, Fernando, Bucciarelli, Eva, Boutorh, Julia, Bouvier, Vincent, Boyle, Edward A., Branellec, Pierre, Carracedo, L., Casacuberta, Nuria, Castrillejo, Maxi, Cheize, Marie, Contreira Pereira, Leonardo, Cossa, Daniel, Daniault, Nathalie, De Saint-Léger, Emmanuel, Dehairs, Frank, Deng, Feifei, Desprez de Gésincourt, Floriane, Devesa, Jérémy, Foliot, Lorna, Fonseca-Batista, Debany, Gallinari, Morgane, García-Ibáñez, Maribel I., Gourain, Arthur, Grossteffan, Emilie, Hamon, Michel, Heimbürger-Boavida, Lars-Eric, Henderson, Gideon M., Jeandel, Catherine, Kermabon, Catherine, Lacan, François, Le Bot, Philippe, Le Goff, Manon, Le Roy, Emilie, Lefèbvre, Alison, Leizour, Stéphane, Lemaitre, Nolwenn, Masqué, Pere, Ménage, Olivier, Menzel Barraqueta, Jan-Lukas, Mercier, Herlé, Perault, Fabien, Pérez, Fiz F., Planquette, Hélène, Planchon, Frédéric, Roukaerts, Arnout, Sanial, Virginie, Sauzède, Raphaëlle, Schmechtig, Catherine, Shelley, Rachel U., Stewart, Gillian, Sutton, Jill N., Tang, Yi, Tisnérat-Laborde, Nadine, Tonnard, Manon, Tréguer, Paul, van Beek, Pieter, Zurbrick, Cheryl M., Zunino, P., LabexMER, Institut Français de Recherche pour l'Exploitation de la Mer, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Sarthou, Géraldine, Lherminier, Pascale, Achterberg, Eric P., Alonso Pérez, Fernando, Bucciarelli, Eva, Boutorh, Julia, Bouvier, Vincent, Boyle, Edward A., Branellec, Pierre, Carracedo, L., Casacuberta, Nuria, Castrillejo, Maxi, Cheize, Marie, Contreira Pereira, Leonardo, Cossa, Daniel, Daniault, Nathalie, De Saint-Léger, Emmanuel, Dehairs, Frank, Deng, Feifei, Desprez de Gésincourt, Floriane, Devesa, Jérémy, Foliot, Lorna, Fonseca-Batista, Debany, Gallinari, Morgane, García-Ibáñez, Maribel I., Gourain, Arthur, Grossteffan, Emilie, Hamon, Michel, Heimbürger-Boavida, Lars-Eric, Henderson, Gideon M., Jeandel, Catherine, Kermabon, Catherine, Lacan, François, Le Bot, Philippe, Le Goff, Manon, Le Roy, Emilie, Lefèbvre, Alison, Leizour, Stéphane, Lemaitre, Nolwenn, Masqué, Pere, Ménage, Olivier, Menzel Barraqueta, Jan-Lukas, Mercier, Herlé, Perault, Fabien, Pérez, Fiz F., Planquette, Hélène, Planchon, Frédéric, Roukaerts, Arnout, Sanial, Virginie, Sauzède, Raphaëlle, Schmechtig, Catherine, Shelley, Rachel U., Stewart, Gillian, Sutton, Jill N., Tang, Yi, Tisnérat-Laborde, Nadine, Tonnard, Manon, Tréguer, Paul, van Beek, Pieter, Zurbrick, Cheryl M., and Zunino, P.

Abstract

The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this special issue (https://www.biogeosciences.net/special_issue900.html), results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 18 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.

Published
2018

23. Supplementary material to "Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise"

Author

Sarthou, Géraldine, primary, Lherminier, Pascale, additional, Achterberg, Eric P., additional, Alonso-Pérez, Fernando, additional, Bucciarelli, Eva, additional, Boutorh, Julia, additional, Bouvier, Vincent, additional, Boyle, Edward A., additional, Branellec, Pierre, additional, Carracedo, Lidia I., additional, Casacuberta, Nuria, additional, Castrillejo, Maxi, additional, Cheize, Marie, additional, Contreira Pereira, Leonardo, additional, Cossa, Daniel, additional, Daniault, Nathalie, additional, De Saint-Léger, Emmanuel, additional, Dehairs, Frank, additional, Deng, Feifei, additional, Desprez de Gésincourt, Floriane, additional, Devesa, Jérémy, additional, Foliot, Lorna, additional, Fonseca-Batista, Debany, additional, Gallinari, Morgane, additional, García-Ibáñez, Maribel I., additional, Gourain, Arthur, additional, Grossteffan, Emilie, additional, Hamon, Michel, additional, Heimbürger, Lars Eric, additional, Henderson, Gideon M., additional, Jeandel, Catherine, additional, Kermabon, Catherine, additional, Lacan, François, additional, Le Bot, Philippe, additional, Le Goff, Manon, additional, Le Roy, Emilie, additional, Lefèbvre, Alison, additional, Leizour, Stéphane, additional, Lemaitre, Nolwenn, additional, Masqué, Pere, additional, Ménage, Olivier, additional, Menzel Barraqueta, Jan-Lukas, additional, Mercier, Herlé, additional, Perault, Fabien, additional, Pérez, Fiz F., additional, Planquette, Hélène F., additional, Planchon, Frédéric, additional, Roukaerts, Arnout, additional, Sanial, Virginie, additional, Sauzède, Raphaëlle, additional, Shelley, Rachel U., additional, Stewart, Gillian, additional, Sutton, Jill N., additional, Tang, Yi, additional, Tisnérat-Laborde, Nadine, additional, Tonnard, Manon, additional, Tréguer, Paul, additional, van Beek, Pieter, additional, Zurbrick, Cheryl M., additional, and Zunino, Patricia, additional

Published
2018
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24. Supplementary material to "Evidence of high N2 fixation rates in productive waters of the temperate Northeast Atlantic"

Author

Fonseca-Batista, Debany, primary, Li, Xuefeng, additional, Riou, Virginie, additional, Michotey, Valérie, additional, Deman, Forian, additional, Fripiat, François, additional, Guasco, Sophie, additional, Brion, Natacha, additional, Lemaitre, Nolwenn, additional, Tonnard, Manon, additional, Gallinari, Morgane, additional, Planquette, Hélène, additional, Planchon, Frédéric, additional, Sarthou, Géraldine, additional, Elskens, Marc, additional, Chou, Lei, additional, and Dehairs, Frank, additional

Published
2018
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25. Evidence of high N2 fixation rates in productive waters of the temperate Northeast Atlantic

Author

Fonseca-Batista, Debany, primary, Li, Xuefeng, additional, Riou, Virginie, additional, Michotey, Valérie, additional, Deman, Forian, additional, Fripiat, François, additional, Guasco, Sophie, additional, Brion, Natacha, additional, Lemaitre, Nolwenn, additional, Tonnard, Manon, additional, Gallinari, Morgane, additional, Planquette, Hélène, additional, Planchon, Frédéric, additional, Sarthou, Géraldine, additional, Elskens, Marc, additional, Chou, Lei, additional, and Dehairs, Frank, additional

Published
2018
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26. High variability of export fluxes along the North Atlantic GEOTRACES section GA01: Particulate organic carbon export deduced from the <sup>234</sup>Th method

Author

Lemaitre, Nolwenn, primary, Planchon, Frédéric, additional, Planquette, Hélène, additional, Dehairs, Frank, additional, Fonseca-Batista, Debany, additional, Roukaerts, Arnout, additional, Deman, Florian, additional, Tang, Yi, additional, Mariez, Clarisse, additional, and Sarthou, Géraldine, additional

Published
2018
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27. Supplementary material to "High variability of export fluxes along the North Atlantic GEOTRACES section GA01: Particulate organic carbon export deduced from the <sup>234</sup>Th method"

Author

Lemaitre, Nolwenn, primary, Planchon, Frédéric, additional, Planquette, Hélène, additional, Dehairs, Frank, additional, Fonseca-Batista, Debany, additional, Roukaerts, Arnout, additional, Deman, Florian, additional, Tang, Yi, additional, Mariez, Clarisse, additional, and Sarthou, Géraldine, additional

Published
2018
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28. Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic

Author

Lemaitre, Nolwenn, primary, Planquette, Hélène, additional, Planchon, Frédéric, additional, Sarthou, Géraldine, additional, Jacquet, Stéphanie, additional, García-Ibáñez, Maribel I., additional, Gourain, Arthur, additional, Cheize, Marie, additional, Monin, Laurence, additional, André, Luc, additional, Laha, Priya, additional, Terryn, Herman, additional, and Dehairs, Frank, additional

Published
2018
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29. Mesopelagic carbon remineralization along the GEOVIDE transect in the North Atlantic (GEOTRACES GA01)

Author

Lemaitre, Nolwenn, Hélène, Planquette, Dehairs, Frank, Monin, Laurence, Andre, Luc, Jacquet, Stephanie, Planchon, Frédéric, Chemistry, Earth System Sciences, Analytical, Environmental & Geo-Chemistry, Faculty of Sciences and Bioengineering Sciences, and Analytical and Environmental Chemistry

Abstract

The international GEOVIDE expedition (GEOTRACES GA01, May-June 2014, spring period) aims at providing a better understanding on key trace metal biogeochemical cycles in the North Atlantic Ocean. Sampling was undertaken at 12 stations located within different biogeochemical provinces including the Iberian Basin, the West European Basin, Reykjanes Ridge, Irminger Sea, Greenland Margin and the Labrador Sea, showing contrasted physical, biological and chemical characteristics. Some of these areas support annually recurrent spring phytoplankton bloom potentially generating a pulse of sinking particles. The carbon transfer is known to be efficient in the North Atlantic, but large uncertainties remain about the remineralization processes affecting the sinking particles in the mesopelagic layer. Carbon remineralization fluxes were traced by the excess, non-lithogenic particulate barium (Baxs) proxy (Dehairs et al., 1997) and revealed large variation between provinces ranging from 61 mg C.m-2.d-1 near the Greenland Margin to 250 mg C.m-2.d-1 in the Labrador Sea (100-1000m depth). This high remineralization flux was probably related to an important bloom developed before the sampling and also to the Labrador Seawater formation generating a deep remineralization layer. Generally, remineralization seems to be an important process questioning the real efficiency of the carbon transfer to the deep North Atlantic Ocean.

Published
2016

30. Particulate barium tracing significant mesopelagic carbon remineralisation in the North Atlantic

Author

Lemaitre, Nolwenn, primary, Planquette, Hélène, additional, Planchon, Frédéric, additional, Sarthou, Géraldine, additional, Jacquet, Stéphanie, additional, García-Ibáñez, Maribel I., additional, Gourain, Arthur, additional, Cheize, Marie, additional, Monin, Laurence, additional, André, Luc, additional, Laha, Priya, additional, Terryn, Herman, additional, and Dehairs, Frank, additional

Published
2017
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31. Supplementary material to "Particulate barium tracing significant mesopelagic carbon remineralisation in the North Atlantic"

Author

Lemaitre, Nolwenn, primary, Planquette, Hélène, additional, Planchon, Frédéric, additional, Sarthou, Géraldine, additional, Jacquet, Stéphanie, additional, García-Ibáñez, Maribel I., additional, Gourain, Arthur, additional, Cheize, Marie, additional, Monin, Laurence, additional, André, Luc, additional, Laha, Priya, additional, Terryn, Herman, additional, and Dehairs, Frank, additional

Published
2017
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32. Carbon export in the naturally iron-fertilized Kerguelen area of the Southern Ocean based on the 234Th approach

Author

Planchon, Frédéric, Ballas, D., Cavagna, A.-J., Bowie, A. R., Davies, D., Trull, T., Laurenceau-Cornec, E. C., Van Der Merwe, P., Dehairs, F., 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), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Antarctic Climate and Ecosystems Cooperative Research Centre (ACE-CRC), Institute for Marine and Antarctic Studies [Hobart] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), CSIRO Marine and Atmosphere Research [Hobart], Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), ANR-10-BLAN-0614,KEOPS 2,Kerguelen : Comparaison plateau Ocean2(2010), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Institute for Marine and Antarctic Studies [Horbat] (IMAS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ACL, lcsh:QE1-996.5, PHYTOPLANKTON BLOOM, lcsh:Life, ATLANTIC SECTOR, ANTARCTIC POLAR FRONT, PARTICLE EXPORT, DISSOLVED IRON, REGION, lcsh:Geology, NITROGEN UPTAKE, lcsh:QH501-531, PLATEAU, lcsh:QH540-549.5, lcsh:Ecology, SPRING BLOOM, PARTICULATE ORGANIC-CARBON, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract

This study examined upper-ocean particulate organic carbon (POC) export using the 234Th approach as part of the second KErguelen Ocean and Plateau compared Study expedition (KEOPS2). Our aim was to characterize the spatial and the temporal variability of POC export during austral spring (October–November 2011) in the Fe-fertilized area of the Kerguelen Plateau region. POC export fluxes were estimated at high productivity sites over and downstream of the plateau and compared to a high-nutrient low-chlorophyll (HNLC) area upstream of the plateau in order to assess the impact of iron-induced productivity on the vertical export of carbon. Deficits in 234Th activities were observed at all stations in surface waters, indicating early scavenging by particles in austral spring. 234Th export was lowest at the reference station R-2 and highest in the recirculation region (E stations) where a pseudo-Lagrangian survey was conducted. In comparison 234Th export over the central plateau and north of the polar front (PF) was relatively limited throughout the survey. However, the 234Th results support that Fe fertilization increased particle export in all iron-fertilized waters. The impact was greatest in the recirculation feature (3–4 fold at 200 m depth, relative to the reference station), but more moderate over the central Kerguelen Plateau and in the northern plume of the Kerguelen bloom (~2-fold at 200 m depth). The C : Th ratio of large (>53 μm) potentially sinking particles collected via sequential filtration using in situ pumping (ISP) systems was used to convert the 234Th flux into a POC export flux. The C : Th ratios of sinking particles were highly variable (3.1 ± 0.1 to 10.5 ± 0.2 μmol dpm−1) with no clear site-related trend, despite the variety of ecosystem responses in the fertilized regions. C : Th ratios showed a decreasing trend between 100 and 200 m depth suggesting preferential carbon loss relative to 234Th possibly due to heterotrophic degradation and/or grazing activity. C : Th ratios of sinking particles sampled with drifting sediment traps in most cases showed very good agreement with ratios for particles collected via ISP deployments (>53 μm particles). Carbon export production varied between 3.5 ± 0.9 and 11.8 ± 1.3 mmol m−2 d−1 from the upper 100 m and between 1.8 ± 0.9 and 8.2 ± 0.9 mmol m−2 d−1 from the upper 200 m. The highest export production was found inside the PF meander with a range of 5.3 ± 1.0 to 11.8 ± 1.1 mmol m−2 d−1 over the 19-day survey period. The impact of Fe fertilization is highest inside the PF meander with 2.9–4.5-fold higher carbon flux at 200 m depth in comparison to the HNLC control station. The impact of Fe fertilization was significantly less over the central plateau (stations A3 and E-4W) and in the northern branch of the bloom (station F-L) with 1.6–2.0-fold higher carbon flux compared to the reference station R. Export efficiencies (ratio of export to primary production and ratio of export to new production) were particularly variable with relatively high values in the recirculation feature (6 to 27 %, respectively) and low values (1 to 5 %, respectively) over the central plateau (station A3) and north of the PF (station F-L), indicating spring biomass accumulation. Comparison with KEOPS1 results indicated that carbon export production is much lower during the onset of the bloom in austral spring than during the peak and declining phases in late summer.

Published
2015

33. High variability of particulate organic carbon export along the North Atlantic GEOTRACES section GA01 as deduced from 234Th fluxes.

Author

Lemaitre, Nolwenn, Planchon, Frédéric, Planquette, Hélène, Dehairs, Frank, Fonseca-Batista, Debany, Roukaerts, Arnout, Deman, Florian, Tang, Yi, Mariez, Clarisse, and Sarthou, Géraldine

Subjects
COLLOIDAL carbon, BIOGEOCHEMISTRY, WATERSHEDS, CYANOBACTERIA, COCCOLITHOPHORES
Abstract

In this study we report particulate organic carbon (POC) export fluxes for different biogeochemical basins in the North Atlantic as part of the GEOTRACES GA01 expedition (GEOVIDE, May-June 2014). Surface POC export fluxes were deduced by combining export fluxes of total Thorium-234 (234Th) with the ratio of POC to 234Th of sinking particles at the depth of export. Particles were collected in two size classes (> 53 and 1-53 μm) using in situ pumps and the large size fraction was considered representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces, ranging from 1.4 mmolm-2 d-1 in the Irminger basin, where the bloom was close to its maximum, to 12 mmolm-2 d-1near the Iberian Margin, where the bloom had already declined. In addition to the state of progress of the bloom, variations of the POC export fluxes were also related to the phytoplankton size and community structure. In line with previous studies, the presence of coccolithophorids and diatoms appeared to enhance the POC export flux, while the dominance of picophytoplankton cells, such as cyanobacteria, resulted in lower fluxes. The ratio of POC export to primary production (PP) strongly varied regionally and was generally low (⩽ 14 %), except at two stations located near the Iberian Margin (35 %) and within the Labrador basin (38 %), which were characterized by unusual low in situ PP. We thus conclude that during the GEOVIDE cruise, the North Atlantic was not as efficient in exporting carbon from the surface, as reported earlier by others. Finally, we also estimated the POC export at 100m below the surface export depth to investigate the POC transfer efficiencies. This parameter was also highly variable amongst regions, with the highest transfer efficiency at sites where coccolithophorids dominated. [ABSTRACT FROM AUTHOR]

Published
2018
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34. Nitrate isotopic composition in the Kerguelen area (Southern Ocean)

Author

Dehairs, Frank, Trull, T.W., Cavagna, Anne Julie, Planchon, Frédéric, Fripiat, François, Chemistry, Analytical and Environmental Chemistry, Earth System Sciences, and Analytical, Environmental & Geo-Chemistry

Abstract

We present water column profiles of δ15N-NO3 and δ18O-NO3 above the Kerguelen Plateau and in a permanent meander of the Polar Front during the early phase of the growth season (Oct. – Nov. 2011, KEOPS 2). δ15N-NO3 ranged from 4.5 to 6.5 ‰ and δ18O-NO3 from 2 to 4.5 ‰ between bottom and surface waters, reflecting that nitrate uptake and isotopic fractionation had been ongoing for some time at this early stage of the growth season. Surprisingly, upper water column isotopic signatures overlapped well with values obtained at the end of season for the same general area (Feb.-Mar. 2005, KEOPS 1; Trull et al., 2008). While silicic acid decreases to very low concentrations, nitrate remains high (>20 µM) over the entire growth season, despite similar silicic acid and nitrate uptake rates (Mosseri et al., 2008). This suggests nitrate is significantly recycled within the upper water column. A simple mass balance model, using nitrate, ammonium uptake rates and particle fluxes and published data on 15N/14N discrimination factors indeed points toward nitrification as a significant nitrate source in the upper water column.

Published
2014

35. Chemometric perspectives on plankton community responses to natural iron fertilization over and downstream of the Kerguelen Plateau in the Southern Ocean

Author

Trull, Thomas W., Dehairs, Frank, Cavagna, Anne Julie, Planchon, Frédéric, Analytical and Environmental Chemistry, Chemistry, and Analytical, Environmental & Geo-Chemistry

Subjects
Kerguelen
Abstract

We examined phytoplankton community responses to natural iron fertilisation at 32 sites over and downstream from the Kerguelen Plateau in the Southern Ocean during the austral spring bloom in October-November 2011. Community structure was estimated from chemical and isotopic measurements (particulate organic carbon POC, 13C-POC, particulate nitrogen PN, 15N-PN, and biogenic silica BSi) on size-fractionated samples from surface waters (300, 210, 50, 20, 5, and 1 ?m fractions). Higher values of 13C-POC (vs. co-located 13C-DIC source values) were taken as indicative of faster growth rates, and higher values of 15N-PN (vs. co-located 15N-NO3 source values) as indicative of greater nitrate use. Community responses varied in relation to both regional circulation and the advance of the bloom. Iron fertilised waters over the plateau developed dominance by very large diatoms (50-210 ?m) with high BSi / POC ratios, high growth rates, and significant ammonium recycling as biomass built up. In contrast, downstream Polar Frontal waters with similar or higher iron supply were dominated by smaller diatoms (20-50 ?m) and exhibited greater ammonium recycling. Stations in a deep water bathymetrically trapped recirculation south of the Polar Front with lower iron levels showed the large cell dominance observed on the plateau, but much less biomass. Comparison of these communities to surface water nitrate (and silicate) depletions as a proxy for export shows that the low biomass recirculation feature exported similar amounts of nitrogen to the high biomass blooms over the plateau and north of the Polar Front. This suggests that trophodynamic and export responses differed between regions with persistent low levels vs. punctual high levels of iron fertilisation.

Published
2014

36. Fe fertilization and carbon export production: the natural laboratory of the Kerguelen Island, Southern Ocean

Author

Planchon, Frédéric, Ballas, Dionysios, Cavagna, Anne Julie, Trull, T.W., Dehairs, Frank, Chemistry, Analytical and Environmental Chemistry, Earth System Sciences, and Analytical, Environmental & Geo-Chemistry

Abstract

The Kerguelen Island area provides a natural laboratory to study the impact of iron fertilization on the biological carbon pump. During the KEOPS2 survey (Kerguelen Ocean Plateau Study, Oct-Nov 2011) we investigated POC sinking fluxes using a 234Th-based approach in combination with free-drifting sediment traps and new production estimates. At all stations, surface waters were depleted in total 234Th activity (234Th/238U ratio: 0.78-0.89) indicating scavenging of thorium with sinking particles. 234Th export flux at 200 m calculated using a steady state assumption was lowest at the off plateau HNLC reference station (449 ± 203) and highest inside the permanent meander of the Polar Front (1995 ± 176 dpm m-2 d-1) downstream of the plateau. 200-m POC export fluxes, calculated using POC/234Th ratios of large (>53 µm) “potentially sinking” particles were highest in the meander of the Polar Front (6.7-8.2) and compared fairly with trap data (2.0-4.9 mmol m-2 d-1). However, overall POC export was low compared to net primary productivity (44-285 mmol m-2 d-1), indicating mixed layer accumulation of biomass during this early season condition.

Published
2014

37. Nitrogen cycling in the Southern Ocean Kerguelen Plateau area: evidence for significant surface nitrification from nitrate isotopic compositions

Author

Dehairs, F., Fripiat, François, Cavagna, A. -J., Trull, Thomas W., Fernandez, C., Davies, D., Roukaerts, Arnout, Fonseca Batista, D., Planchon, Frédéric, Elskens, M., Dehairs, F., Fripiat, François, Cavagna, A. -J., Trull, Thomas W., Fernandez, C., Davies, D., Roukaerts, Arnout, Fonseca Batista, D., Planchon, Frédéric, and Elskens, M.

Abstract

This paper presents whole water column data for nitrate N, O isotopic composition for the Kerguelen Plateau area and the basin extending east of Heard Island, aiming at understanding the N-cycling in this naturally iron fertilized area that is characterized by large re-current phytoplankton blooms. The KEOPS 2 expedition (October–November 2011) took place in spring season and complements knowledge gathered during an earlier summer expedition to the same area (KEOPS 1, February–March 2005). As noted by others a remarkable condition of the system is the moderate consumption of nitrate over the season (nitrate remains >20 μM) while silicic acid becomes depleted, suggesting significant recycling of nitrogen. Nitrate isotopic signatures in the upper water column do mimic this condition, with surprising overlap of spring and summer regressions of δ18ONO3 vs. δ15NNO3 isotopic compositions. These regressions obey rather closely the 18&varepsilon;/15&varepsilon; discrimination expected for nitrate uptake (18&varepsilon;/15&varepsilon; = 1), but regression slopes as large as 1.6 were observed for the mixed layer above the Kerguelen Plateau. A preliminarily mass balance calculation for the early bloom period points toward significant nitrification occurring in the mixed layer and which may be equivalent to up to 47% of nitrate uptake above the Kerguelen Plateau. A further finding concerns deep ocean low δ18ONO3 values (<2‰) underlying high chlorophyll waters at the Polar Front Zone and which cannot be explained by remineralization and nitrification of the local particulate nitrogen flux, which is too small in magnitude. However, the studied area is characterized by a complex recirculation pattern that would keep deep waters in the area and could impose a seasonally integrated signature of surface water processes on the deep waters., info:eu-repo/semantics/published

Published
2015

38. The GEOTRACES Intermediate Data Product 2014

Author

Mawji, Edward, Schlitzer, Reiner, Dodas, Elena Masferrer, Abadie, Cyril, Abouchami, Wafa, Anderson, Robert F., Baars, Oliver, Bakker, Karel, Baskaran, Mark, Bates, Nicholas R., Bluhm, Katrin, Bowie, Andrew, Bown, Johann, Boye, Marie, Boyle, Edward A., Branellec, Pierre, Bruland, Kenneth W., Brzezinski, Mark A., Bucciarelli, Eva, Buesseler, Ken, Butler, Edward, Cai, Pinghe, Cardinal, Damien, Casciotti, Karen, Chaves, Joaquin, Cheng, Hai, Chever, Fanny, Church, Thomas M., Colman, Albert S., Conway, Tim M., Croot, Peter L., Cutter, Gregory A., de Baar, Hein J.W., de Souza, Gregory F., Dehairs, Frank, Deng, Feifei, Dieu, Huong Thi, Dulaquais, Gabriel, Echegoyen-Sanz, Yolanda, Lawrence Edwards, R., Fahrbach, Eberhard, Fitzsimmons, Jessica, Fleisher, Martin, Frank, Martin, Friedrich, Jana, Fripiat, François, Galer, Stephen J.G., Gamo, Toshitaka, Solsona, Ester Garcia, Gerringa, Loes J.A., Godoy, José Marcus, Gonzalez, Santiago, Grossteffan, Emilie, Hatta, Mariko, Hayes, Christopher T., Heller, Maija Iris, Henderson, Gideon, Huang, Kuo-Fang, Jeandel, Catherine, Jenkins, William J., John, Seth, Kenna, Timothy C., Klunder, Maarten, Kretschmer, Sven, Kumamoto, Yuichiro, Laan, Patrick, Labatut, Marie, Lacan, Francois, Lam, Phoebe J., Lannuzel, Delphine, le Moigne, Frederique, Lechtenfeld, Oliver J., Lohan, Maeve C., Lu, Yanbin, Masqué, Pere, McClain, Charles R., Measures, Christopher, Middag, Rob, Moffett, James, Navidad, Alicia, Nishioka, Jun, Noble, Abigail, Obata, Hajime, Ohnemus, Daniel C., Owens, Stephanie, Planchon, Frédéric, Pradoux, Catherine, Puigcorbé, Viena, Quay, Paul, Radic, Amandine, Rehkämper, Mark, Remenyi, Tomas, Rijkenberg, Micha J.A., Rintoul, Stephen, Robinson, Laura F., Roeske, Tobias, Rosenberg, Mark, van der Loeff, Michiel Rutgers, Ryabenko, Evgenia, Saito, Mak A., Roshan, Saeed, Salt, Lesley, Sarthou, Géraldine, Schauer, Ursula, Scott, Peter, Sedwick, Peter N., Sha, Lijuan, Shiller, Alan M., Sigman, Daniel M., Smethie, William, Smith, Geoffrey J., Sohrin, Yoshiki, Speich, Sabrina, Stichel, Torben, Stutsman, Johnny, Swift, James H., Tagliabue, Alessandro, Thomas, Alexander, Tsunogai, Urumu, Twining, Benjamin S., van Aken, Hendrik M., van Heuven, Steven, van Ooijen, Jan, van Weerlee, Evaline, Venchiarutti, Celia, Voelker, Antje H.L., Wake, Bronwyn, Warner, Mark J., Woodward, E. Malcolm S., Wu, Jingfeng, Wyatt, Neil, Yoshikawa, Hisayuki, Zheng, Xin-Yuan, Xue, Zichen, Zieringer, Moritz, Zimmer, Louise A., Mawji, Edward, Schlitzer, Reiner, Dodas, Elena Masferrer, Abadie, Cyril, Abouchami, Wafa, Anderson, Robert F., Baars, Oliver, Bakker, Karel, Baskaran, Mark, Bates, Nicholas R., Bluhm, Katrin, Bowie, Andrew, Bown, Johann, Boye, Marie, Boyle, Edward A., Branellec, Pierre, Bruland, Kenneth W., Brzezinski, Mark A., Bucciarelli, Eva, Buesseler, Ken, Butler, Edward, Cai, Pinghe, Cardinal, Damien, Casciotti, Karen, Chaves, Joaquin, Cheng, Hai, Chever, Fanny, Church, Thomas M., Colman, Albert S., Conway, Tim M., Croot, Peter L., Cutter, Gregory A., de Baar, Hein J.W., de Souza, Gregory F., Dehairs, Frank, Deng, Feifei, Dieu, Huong Thi, Dulaquais, Gabriel, Echegoyen-Sanz, Yolanda, Lawrence Edwards, R., Fahrbach, Eberhard, Fitzsimmons, Jessica, Fleisher, Martin, Frank, Martin, Friedrich, Jana, Fripiat, François, Galer, Stephen J.G., Gamo, Toshitaka, Solsona, Ester Garcia, Gerringa, Loes J.A., Godoy, José Marcus, Gonzalez, Santiago, Grossteffan, Emilie, Hatta, Mariko, Hayes, Christopher T., Heller, Maija Iris, Henderson, Gideon, Huang, Kuo-Fang, Jeandel, Catherine, Jenkins, William J., John, Seth, Kenna, Timothy C., Klunder, Maarten, Kretschmer, Sven, Kumamoto, Yuichiro, Laan, Patrick, Labatut, Marie, Lacan, Francois, Lam, Phoebe J., Lannuzel, Delphine, le Moigne, Frederique, Lechtenfeld, Oliver J., Lohan, Maeve C., Lu, Yanbin, Masqué, Pere, McClain, Charles R., Measures, Christopher, Middag, Rob, Moffett, James, Navidad, Alicia, Nishioka, Jun, Noble, Abigail, Obata, Hajime, Ohnemus, Daniel C., Owens, Stephanie, Planchon, Frédéric, Pradoux, Catherine, Puigcorbé, Viena, Quay, Paul, Radic, Amandine, Rehkämper, Mark, Remenyi, Tomas, Rijkenberg, Micha J.A., Rintoul, Stephen, Robinson, Laura F., Roeske, Tobias, Rosenberg, Mark, van der Loeff, Michiel Rutgers, Ryabenko, Evgenia, Saito, Mak A., Roshan, Saeed, Salt, Lesley, Sarthou, Géraldine, Schauer, Ursula, Scott, Peter, Sedwick, Peter N., Sha, Lijuan, Shiller, Alan M., Sigman, Daniel M., Smethie, William, Smith, Geoffrey J., Sohrin, Yoshiki, Speich, Sabrina, Stichel, Torben, Stutsman, Johnny, Swift, James H., Tagliabue, Alessandro, Thomas, Alexander, Tsunogai, Urumu, Twining, Benjamin S., van Aken, Hendrik M., van Heuven, Steven, van Ooijen, Jan, van Weerlee, Evaline, Venchiarutti, Celia, Voelker, Antje H.L., Wake, Bronwyn, Warner, Mark J., Woodward, E. Malcolm S., Wu, Jingfeng, Wyatt, Neil, Yoshikawa, Hisayuki, Zheng, Xin-Yuan, Xue, Zichen, Zieringer, Moritz, and Zimmer, Louise A.

Published
2015

39. Significant mixed layer nitrification in a natural iron-fertilized bloom of the Southern Ocean

Author

Gordon Research Seminar on polar marine sciences (Lucca, Italy), Fripiat, François, Elskens, Marc, Trull, Thomas W., Blain, S., Cavagna, A. -J., Fernandez, C., Fonseca-Batista, Debany, Planchon, Frédéric, Roukaerts, Arnout, Dehairs, F., Gordon Research Seminar on polar marine sciences (Lucca, Italy), Fripiat, François, Elskens, Marc, Trull, Thomas W., Blain, S., Cavagna, A. -J., Fernandez, C., Fonseca-Batista, Debany, Planchon, Frédéric, Roukaerts, Arnout, and Dehairs, F.

Abstract

info:eu-repo/semantics/nonPublished

Published
2015

40. Significant mixed layer nitrification in a natural iron-fertilized bloom of the Southern Ocean

Author

Fripiat, François, Elskens, M., Trull, Thomas W., Blain, S., Cavagna, A. -J., Fernandez, C., Fonseca-Batista, D., Planchon, Frédéric, Raimbault, P., Roukaerts, Arnout, Dehairs, F., Fripiat, François, Elskens, M., Trull, Thomas W., Blain, S., Cavagna, A. -J., Fernandez, C., Fonseca-Batista, D., Planchon, Frédéric, Raimbault, P., Roukaerts, Arnout, and Dehairs, F.

Abstract

Nitrification, the microbially mediated oxidation of ammonium into nitrate, is generally expected to be low in the Southern Ocean mixed layer. This paradigm assumes that nitrate is mainly provided through vertical mixing and assimilated during the vegetative season, supporting the concept that nitrate uptake is equivalent to the new primary production (i.e. primary production which is potentially available for export). Here we show that nitrification is significant (~40–80% of the seasonal nitrate uptake) in the naturally iron-fertilized bloom over the southeast Kerguelen Plateau. Hence, a large fraction of the nitrate-based primary production is regenerated, instead of being exported. It appears that nitrate assimilation (light dependent) and nitrification (partly light inhibited) are spatially separated between the upper and lower parts, respectively, of the deep surface mixed layers. These deep mixed layers, extending well below the euphotic layer, allow nitrifiers to compete with phytoplankton for the assimilation of ammonium. The high contributions of nitrification to nitrate uptake are in agreement with both low export efficiency (i.e. the percentage of primary production that is exported) and low seasonal nitrate drawdown despite high nitrate assimilation., info:eu-repo/semantics/published

Published
2015

41. Significant mixed layer nitrification in a natural iron-fertilized bloom of the Southern Ocean

Author

Gordon Research Seminar on polar marine sciences (2015: Lucca, Italy), Fripiat, François, Elskens, Marc, Trull, Thomas W., Blain, S., Cavagna, A. -J., Fernandez, C., Fonseca-Batista, Debany, Planchon, Frédéric, Roukaerts, Arnout, Dehairs, F., Gordon Research Seminar on polar marine sciences (2015: Lucca, Italy), Fripiat, François, Elskens, Marc, Trull, Thomas W., Blain, S., Cavagna, A. -J., Fernandez, C., Fonseca-Batista, Debany, Planchon, Frédéric, Roukaerts, Arnout, and Dehairs, F.

Abstract

info:eu-repo/semantics/nonPublished

Published
2015

42. The GEOTRACES Intermediate Data Product 2014

Author

Mawji, Edward, primary, Schlitzer, Reiner, additional, Dodas, Elena Masferrer, additional, Abadie, Cyril, additional, Abouchami, Wafa, additional, Anderson, Robert F., additional, Baars, Oliver, additional, Bakker, Karel, additional, Baskaran, Mark, additional, Bates, Nicholas R., additional, Bluhm, Katrin, additional, Bowie, Andrew, additional, Bown, Johann, additional, Boye, Marie, additional, Boyle, Edward A., additional, Branellec, Pierre, additional, Bruland, Kenneth W., additional, Brzezinski, Mark A., additional, Bucciarelli, Eva, additional, Buesseler, Ken, additional, Butler, Edward, additional, Cai, Pinghe, additional, Cardinal, Damien, additional, Casciotti, Karen, additional, Chaves, Joaquin, additional, Cheng, Hai, additional, Chever, Fanny, additional, Church, Thomas M., additional, Colman, Albert S., additional, Conway, Tim M., additional, Croot, Peter L., additional, Cutter, Gregory A., additional, de Baar, Hein J.W., additional, de Souza, Gregory F., additional, Dehairs, Frank, additional, Deng, Feifei, additional, Dieu, Huong Thi, additional, Dulaquais, Gabriel, additional, Echegoyen-Sanz, Yolanda, additional, Lawrence Edwards, R., additional, Fahrbach, Eberhard, additional, Fitzsimmons, Jessica, additional, Fleisher, Martin, additional, Frank, Martin, additional, Friedrich, Jana, additional, Fripiat, François, additional, Galer, Stephen J.G., additional, Gamo, Toshitaka, additional, Solsona, Ester Garcia, additional, Gerringa, Loes J.A., additional, Godoy, José Marcus, additional, Gonzalez, Santiago, additional, Grossteffan, Emilie, additional, Hatta, Mariko, additional, Hayes, Christopher T., additional, Heller, Maija Iris, additional, Henderson, Gideon, additional, Huang, Kuo-Fang, additional, Jeandel, Catherine, additional, Jenkins, William J., additional, John, Seth, additional, Kenna, Timothy C., additional, Klunder, Maarten, additional, Kretschmer, Sven, additional, Kumamoto, Yuichiro, additional, Laan, Patrick, additional, Labatut, Marie, additional, Lacan, Francois, additional, Lam, Phoebe J., additional, Lannuzel, Delphine, additional, le Moigne, Frederique, additional, Lechtenfeld, Oliver J., additional, Lohan, Maeve C., additional, Lu, Yanbin, additional, Masqué, Pere, additional, McClain, Charles R., additional, Measures, Christopher, additional, Middag, Rob, additional, Moffett, James, additional, Navidad, Alicia, additional, Nishioka, Jun, additional, Noble, Abigail, additional, Obata, Hajime, additional, Ohnemus, Daniel C., additional, Owens, Stephanie, additional, Planchon, Frédéric, additional, Pradoux, Catherine, additional, Puigcorbé, Viena, additional, Quay, Paul, additional, Radic, Amandine, additional, Rehkämper, Mark, additional, Remenyi, Tomas, additional, Rijkenberg, Micha J.A., additional, Rintoul, Stephen, additional, Robinson, Laura F., additional, Roeske, Tobias, additional, Rosenberg, Mark, additional, van der Loeff, Michiel Rutgers, additional, Ryabenko, Evgenia, additional, Saito, Mak A., additional, Roshan, Saeed, additional, Salt, Lesley, additional, Sarthou, Géraldine, additional, Schauer, Ursula, additional, Scott, Peter, additional, Sedwick, Peter N., additional, Sha, Lijuan, additional, Shiller, Alan M., additional, Sigman, Daniel M., additional, Smethie, William, additional, Smith, Geoffrey J., additional, Sohrin, Yoshiki, additional, Speich, Sabrina, additional, Stichel, Torben, additional, Stutsman, Johnny, additional, Swift, James H., additional, Tagliabue, Alessandro, additional, Thomas, Alexander, additional, Tsunogai, Urumu, additional, Twining, Benjamin S., additional, van Aken, Hendrik M., additional, van Heuven, Steven, additional, van Ooijen, Jan, additional, van Weerlee, Evaline, additional, Venchiarutti, Celia, additional, Voelker, Antje H.L., additional, Wake, Bronwyn, additional, Warner, Mark J., additional, Woodward, E. Malcolm S., additional, Wu, Jingfeng, additional, Wyatt, Neil, additional, Yoshikawa, Hisayuki, additional, Zheng, Xin-Yuan, additional, Xue, Zichen, additional, Zieringer, Moritz, additional, and Zimmer, Louise A., additional

Published
2015
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43. Evidence of high N2 fixation rates in productive waters of the temperate Northeast Atlantic.

Author

Fonseca-Batista, Debany, Xuefeng Li, Riou, Virginie, Michotey, Valérie, Deman, Forian, Fripiat, François, Guasco, Sophie, Brion, Natacha, Lemaitre, Nolwenn, Tonnard, Manon, Gallinari, Morgane, Planquette, Hélène, Planchon, Frédéric, Sarthou, Géraldine, Elskens, Marc, Lei Chou, and Dehairs, Frank

Subjects
NITROGEN fixation, TEMPERATE climate, PRIMARY productivity (Biology), HETEROTROPHIC bacteria
Abstract

Diazotrophic activity and primary production (PP) were investigated along two transects (Belgica BG2014/14 and GEOVIDE cruises) off the western Iberian Margin and the Bay of Biscay (38.8–46.5° N; 8.0–19.7° W) in May 2014 close to the end of the spring bloom. We report substantial N2 fixation activities, reaching up to 65 nmol N L−1 d−1 and 1533 µmol N m−2 d−1 close to the Iberian Margin between 38.8° N and 40.7° N. Similar figures in the basin have only been reported in the temperate and tropical western North Atlantic waters with coastal, shelf or mesohaline characteristics, as opposed to the mostly open ocean conditions studied here. In agreement with previous studies, the qualitative assessment of nifH gene diversity (encoding the nitrogenase enzyme that fixes N2) suggested a predominance of heterotrophic diazotrophs, and the absence of filamentous cyanobacteria. At the sites where N2 fixation activity was highest sequences affiliated to UCYN-A1, obligate symbiont of eukaryotic prymnesiophyte algae, were recovered. The remaining phylotypes were non-cyanobacterial diazotrophs, known to live in association with suspended particles and zooplankton (i.e., Bacteroidetes, Firmicutes and Proteobacteria). Outside the area of exceptional activity, N2 fixation in the open ocean and at shelf-influenced sites was also relatively high, ranging from 81 to 384 µmol N m−2 d−1, but was undetectable in the central Bay of Biscay. We propose that the unexpectedly high heterotrophic N2 fixation activity recorded at the time of our study was sustained by the availability of phytoplankton derived organic matter (dissolved and/or particulate) resulting from the ongoing to post spring bloom. We pose that this organic material not only sustained bacterial production, but also provided sufficient nutrients essential for the nitrogenase activity (e.g., phosphorus). Dissolved Fe was supplied through atmospheric dust deposition during the month preceding our study and through advection of surface waters from the subtropical region and the shelf area. Our findings stress the need for a more detailed monitoring of the spatial and temporal distribution of oceanic N2 fixation in productive waters of the temperate North Atlantic to better constrain the basin-scale nitrogen input to the ocean inventory. [ABSTRACT FROM AUTHOR]

Published
2018
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44. High variability of export fluxes along the North Atlantic GEOTRACES section GA01: Particulate organic carbon export deduced from the 234Th method.

Author

Lemaitre, Nolwenn, Planchon, Frédéric, Planquette, Hélène, Dehairs, Frank, Fonseca-Batista, Debany, Roukaerts, Arnout, Deman, Florian, Yi Tang, Mariez, Clarisse, and Sarthou, Géraldine

Subjects
BIOGEOCHEMICAL cycles, PHYTOPLANKTON, CYANOBACTERIA, COCCOLITHOPHORES, DIATOMS
Abstract

In this study, we report Particulate Organic Carbon (POC) export fluxes estimated using the 234Th-based approach in different biogeochemical basins of the North Atlantic, as part of the GEOTRACES GA01 expedition (GEOVIDE, May-June 2014). Surface POC export fluxes were deduced by combining export fluxes of 234Th with the POC to 234Th ratio of sinking particles at the depth of export. Particles were collected in two size classes (> 53 µm and 1-53 µm) using in-situ pumps and the large size fraction was considered as representative of sinking material. Surface POC export fluxes revealed latitudinal variations between provinces ranging from 1.4 mmol C m-2 d-1 in the Irminger basin where the bloom was close to its maximum peak, to 12 mmol C m-2 d-1 near the Iberian Margin where the bloom had already declined. In addition to the bloom staging, the variations of POC export fluxes were also related to the phytoplankton community structure. In line with previous studies, the presence of coccolithophorids and diatoms appeared to increase the POC export flux while stations dominated by pico-phytoplankton cells, such as cyanobacteria, were characterized by lower fluxes. The surface POC export fluxes were then compared to in-situ and satellite primary production (PP) in order to assess the export efficiency. This ratio strongly varied regionally and was generally low (≤ 14 %), except at two stations located near the Iberian margin (35 %) and within the Labrador basin (38 %), which were characterized by unusual low in-situ PP. We thus conclude that the North Atlantic during this period was not as efficient in exporting carbon from the surface, as described in recent studies. Finally, we estimated the flux of POC exported 100 m below the surface export depth in order to investigate the transfer efficiency along the section. This parameter was also highly regional-dependent but the lowest attenuation of the POC flux was observed at stations where coccolithophorids dominated. [ABSTRACT FROM AUTHOR]

Published
2018
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46. Nitrate isotopic composition in the Kerguelen area (Southern Ocean)

Author

Ocean Science Meeting (2014: Honolulu, Hawaii), Dehairs, F., Trull, Thomas W., Cavagna, A. -J., Planchon, Frédéric, Fripiat, François, Ocean Science Meeting (2014: Honolulu, Hawaii), Dehairs, F., Trull, Thomas W., Cavagna, A. -J., Planchon, Frédéric, and Fripiat, François

Abstract

info:eu-repo/semantics/published

Published
2014

47. Bivalve Biomineralisation archival potential and proxy incorporation

Author

Andre, Luc, Dehairs, Frank, Mas, Remy, Planchon, Frédéric, Versteegh, Emma, Earth System Sciences, and Geology

Subjects
Paleoclimate
Abstract

This volume examines the potential of bivalves as paleoclimate recorders based on their modern incorporation of selected proxy signals.

Published
2009

48. Bivalves for salinity reconstruction: the case of Mytillus Edulis (the blue mussel)

Author

Mas, Remy, Beelaerts, Veerle, Bauwens, Maite, Servaes, Fabrice, Planchon, Frédéric, Andre, Luc, Schoukens, Joannes, Keppens, Edward, Claeys, Philippe, Dehairs, Frank, Earth System Sciences, Analytical and Environmental Chemistry, Chemistry, Isotope Geology and Evolution of Paleo-Environmnents, Electricity, and Geology

Subjects
Mytillus Edulis, bivalves
Abstract

Testing climate models for future and past climate change critically depend on our ability to quantitatively reconstruct past climate. This requires the proper deconvolution of temperature and salinity effects on proxy incorporation. Paleosalinity is the single most important oceanographic parameter which currently can still not be quantified from sedimentary records. During the PaleoSalt project focus was on the development of proxy-tools allowing past salinity reconstructions from carbonate archives. Our research team selected a marine bivalve which is tolerant to a wide range of salinities and is available also from archaeological collections. The fast growing and relatively short-lived blue mussel also offers the potential to investigate seasonal variability and amplitudes. Our objectives were to refine existing proxy tools such as d18Oc (calibration and signal treatment) and to develop new proxies (dD, isotopes of Mg and trace elements; i.e. a multi-proxy approach) as well as mathematical tools to improve the robustness and sensitivity of reconstructions of environmental conditions. To that purpose we have used two parallel approaches: an in situ study along the salinity gradient of the Scheldt estuary and an ex situ growth experiment under controlled laboratory conditions. Though the d18O results for shells grown under controlled conditions of temperature, salinity and food supply validate the existing equations for temperature reconstruction based on d18O water (e.g. Wanamaker et al., 2006), the carbonate system of the growth medium stands up as an important additional control factor that needs to be taken into account. Other methodologies are being developed for the identification of lipid compounds and their dD signature in shell organic matter and for the assessment of dMg in shell and tissue material, as potential salinity proxies. We recently acquired a new Fast Excimer (193 nm) Laser - ICP-MS system to investigate trace element records in the mussel shells from the controlled growth experiments andSchelde sites and first results will possibly be schown. We also developed mathematical tools to correct for bias in proxy records due to variable growth rate induced time base distortion and to correct the averaging effect that can be induced when sampling the shell. Finally a multi-proxy model was developed for temperature and salinity reconstruction .

Published
2008

49. Particulate barium tracing significant mesopelagic carbon remineralisation in the North Atlantic.

Author

Lemaitre, Nolwenn, Planquette, Hélène, Planchon, Frédéric, Sarthou, Géraldine, Jacquet, Stéphanie, García-Ibáñez, Maribel I., Gourain, Arthur, Cheize, Marie, Monin, Laurence, André, Luc, Laha, Priya, Terryn, Herman, and Dehairs, Frank

Subjects
CYANOBACTERIA, CARBON sequestration, PARTICULATE matter, PHYTOPLANKTON, BARIUM
Abstract

The remineralisation of sinking particles by prokaryotic heterotrophic activities is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May-June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100-1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L-1), which was attributed to an intense bloom averaging 6 mg Chl-a m-3 between January and June 2014 and by an intense 1500 m-deep convection in the central Labrador Sea during the winter preceding the sampling. This downwelling could have promoted a deepening of the prokaryotic heterotrophic activity, increasing the Baxs content. In comparison, the temperate province, characterized by the lowest Baxs content (391 pmol L-1), was sampled during the bloom period and phytoplankton appear to be dominated by small and calcifying species, such as coccolithophorids. The Baxs content, related to an oxygen consumption, was converted into a remineralisation flux using an updated relationship, proposed for the first time in the North Atlantic. The estimated fluxes were in the same order of magnitude than other fluxes obtained by independent methods (moored sediment traps, incubations) in the North Atlantic. Interestingly, in the subpolar and subtropical provinces, mesopelagic POC remineralisation fluxes (up to 13 and 4.6 mmol C m-2 d-1, respectively) were equalling and occasionally even exceeding upper ocean POC export fluxes, highlighting the important impact of the mesopelagic remineralisation on the biological carbon pump with a near-zero, deep (> 1000 m) carbon sequestration efficiency in spring 2014. [ABSTRACT FROM AUTHOR]

Published
2017
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50. Trace elements in Vostok Antarctic ice during the last four climatic cycles [rapid communication]

Author

Gabrielli, Paolo, Planchon, Frédéric, Hong, Sungmin, Lee, Khang Hyun, Hur, Soon Do, Barbante, Carlo, Ferrari, Christophe P., Petit, Jean Robert, Lipenkov, Vladimir Y., Cescon, Paolo, Boutron, Claude F., Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Institute for the Dynamics of Environmental Processes-CNR, University of Ca’ Foscari [Venice, Italy], Korea Polar Research Institute (KOPRI), Environmental Sciences Department, Polytech Grenoble (Institut Universitaire de France), Université Joseph Fourier - Grenoble 1 (UJF), Arctic and Antarctic Research Institute (AARI), Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet), ENEA the Institut Universitaire de France, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)

Subjects
Vostok, ice, trace elements, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, climate
Abstract

International audience; Li, V, Cr, Mn, Co, As, Rb, Sr, Ba, Bi and U were determined by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) in various sections of the 3623 m Vostok deep Antarctic ice core dated from 4600 to 410,000 years BP, which corresponds to the last four climatic cycles back to isotopic stage 11.3. Concentrations of all elements were found to be highly variable with low values during interglacial periods and warm interstadials and much higher values during the coldest periods of the last four ice ages. Crustal enrichment factors suggest various sources for the different elements. Rock and soil dust is the dominant source of V, Mn, Rb, Ba and U whatever the period, and of Li, Cr, Co, Sr and As during cold periods. Sea salt aerosol, together with aeolian dust, also contributes significantly to Sr whereas volcanic emissions could provide a significant input for As and Bi especially during warm periods.

Published
2005

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