Instrumented elephant seals reveal the seasonality in chlorophyll and light-mixing regime in the iron-fertilized Southern Ocean

• Published in: Geophysical Research Letters
• Main Authors: Blain, Stéphane, Renaut, Sophie, Xing, Xiaogang, Claustre, Hervé, Guinet, Christophe
• Other Authors: Laboratoire d'Océanographie Microbienne (LOMIC), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDE]Environmental Sciences; Kerguelen; Kerguelen Island; Southern Ocean; Elephant Seals
• Online Access: https://hal.archives-ouvertes.fr/hal-00961531; https://hal.archives-ouvertes.fr/hal-00961531/document; https://hal.archives-ouvertes.fr/hal-00961531/file/2013GL058065.pdf; https://doi.org/10.1002/2013GL058065

International audience We analyze an original large data set of concurrent in situ measurements of fluorescence, temperature and salinity provided by sensors mounted on the elephant seals of Kerguelen Island. Our results were mainly gathered in regions of the Southern Ocean where the typical iron limitation is relieved by natural iron fertilization. Thus the role of light as the proximal factor of control of phytoplankton can be examined. We show that self-shading, and consequently stratification, are major factors controlling the integrated biomass during the bloom induced by iron fertilization. When the mixed layer was the shallowest, the maximum ChlMLachievable by the given light-mixing regime was however not reached, most likely due to silicic acid limitation. We also show that a favorable light-mixing regime prevails after the spring equinox and is maintained for roughly seven months (October-April). Citation: Blain, S., S. Renaut, X. Xing, H. Claustre, and C. Guinet (2013), Instrumented elephant seals reveal the seasonality in chlorophyll and light-mixing regime in the ironfertilized Southern Ocean.