Wind-driven upwelling of iron sustains dense blooms and food webs in the eastern Weddell Gyre

• Published in: Nature Communications
• Main Authors: Moreau, Sebastien, Hattermann, Tore, de Steur, Laura, Kauko, Hanna, Ahonen, Heidi, Ardelan, Murat, Assmy, Philipp, Chierici, Melissa, Descamps, Sebastien, Dinter, Tilman, Falkenhaug, Tone, Fransson, Agneta, Grønningsæter, Eirik, Hallfredsson, Elvar, Huhn, Oliver, Lebrun, Anais, Lowther, Andrew, Lübcker, Nico, Monteiro, Pedro, Peeken, Ilka, Roychoudhury, Alakendra, Różańska, Magdalena, Ryan-Keogh, Thomas, Sanchez, Nicolas, Singh, Asmita, Simonsen, Jan Henrik, Steiger, Nadine, Thomalla, Sandy, van Tonder, Andre, Wiktor, Jozef, Steen, Harald
• Other Authors: Norwegian Polar Institute, Norwegian University of Science and Technology (NTNU), Institute of Marine Research Bergen (IMR), University of Bergen (UiB), Alfred Wegener Institute, Bremerhaven, Flødevigen Research Station (IMR), University of Bergen (UiB)-University of Bergen (UiB), Institute of Environmental Physics Bremen (IUP), University of Bremen, 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), The University of New Mexico Albuquerque, Southern Ocean Carbon and Climate Observatory (SOCCO), Council for Scientific and Industrial Research Pretoria (CSIR), Stellenbosch University, Institute of Oceanology, Polish Academy of Sciences (IO-PAN), Polska Akademia Nauk = Polish Academy of Sciences = Académie polonaise des sciences (PAN), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Marine Research Institute, University of Cape Town, University of Pretoria South Africa
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDE]Environmental Sciences; Antarc*; Antarctic; Antarctic Krill; baleen whales; Sea ice; Southern Ocean
• Online Access: https://hal.science/hal-04039130; https://hal.science/hal-04039130/document; https://hal.science/hal-04039130/file/s41467-023-36992-1.pdf; https://doi.org/10.1038/s41467-023-36992-1

International audience Abstract The Southern Ocean is a major sink of anthropogenic CO2 and an important foraging area for top trophic level consumers. However, iron limitation sets an upper limit to primary productivity. Here we report on a considerably dense late summer phytoplankton bloom spanning 9000 km 2 in the open ocean of the eastern Weddell Gyre. Over its 2.5 months duration, the bloom accumulated up to 20 g C m −2 of organic matter, which is unusually high for Southern Ocean open waters. We show that, over 1997–2019, this open ocean bloom was likely driven by anomalies in easterly winds that push sea ice southwards and favor the upwelling of Warm Deep Water enriched in hydrothermal iron and, possibly, other iron sources. This recurring open ocean bloom likely facilitates enhanced carbon export and sustains high standing stocks of Antarctic krill, supporting feeding hot spots for marine birds and baleen whales.