Coccolithophore biodiversity controls carbonate export in the Southern Ocean
Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO 3 ) production and export to the deep...
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ftcopernicus:oai:publications.copernicus.org:bgd79864 2023-05-15T18:24:09+02:00 Coccolithophore biodiversity controls carbonate export in the Southern Ocean Rigual Hernández, Andrés S. Trull, Thomas W. Nodder, Scott D. Flores, José A. Bostock, Helen Abrantes, Fátima Eriksen, Ruth S. Sierro, Francisco J. Davies, Diana M. Ballegeer, Anne-Marie Fuertes, Miguel A. Northcote, Lisa C. 2019-09-09 application/pdf https://doi.org/10.5194/bg-2019-352 https://www.biogeosciences-discuss.net/bg-2019-352/ eng eng doi:10.5194/bg-2019-352 https://www.biogeosciences-discuss.net/bg-2019-352/ eISSN: 1726-4189 Text 2019 ftcopernicus https://doi.org/10.5194/bg-2019-352 2019-12-24T09:48:34Z Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO 3 ) production and export to the deep sea. Therefore, changes in the composition and abundance of Southern Ocean coccolithophore populations are likely to alter the marine carbon cycle, with feedbacks to the rate of global climate change. However, the contribution of coccolithophores to CaCO 3 export in the Southern Ocean is uncertain, particularly in the circumpolar Subantarctic Zone that represents about half of the areal extent of the Southern Ocean and where coccolithophores are most abundant. Here, we present measurements of annual CaCO 3 flux and quantitatively partition them amongst coccolithophore species and heterotrophic calcifiers at two sites representative of a large portion of the Subantarctic Zone. We find that coccolithophores account for a major fraction of the annual CaCO 3 export with highest contributions in waters with low algal biomass accumulations. Notably, our analysis reveals that although Emiliania huxleyi is an important vector for CaCO 3 export to the deep sea, less abundant but larger species account for most of the annual coccolithophore CaCO 3 flux. This observation contrasts with satellite remote sensing images that mostly reflect E. huxleyi blooms as a result of its higher cell abundance and detachment of its relatively small liths. It appears likely that the climate-induced migration of oceanic fronts will initially result in the poleward expansion of large coccolithophore species increasing CaCO 3 production. However, subantarctic coccolithophore populations will eventually diminish as acidification overwhelms those changes. Overall, our analysis emphasizes the need for species-centred studies to improve our ability to project future changes in phytoplankton communities and their influence on marine biogeochemical cycles. Text Southern Ocean Copernicus Publications: E-Journals Southern Ocean |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO 3 ) production and export to the deep sea. Therefore, changes in the composition and abundance of Southern Ocean coccolithophore populations are likely to alter the marine carbon cycle, with feedbacks to the rate of global climate change. However, the contribution of coccolithophores to CaCO 3 export in the Southern Ocean is uncertain, particularly in the circumpolar Subantarctic Zone that represents about half of the areal extent of the Southern Ocean and where coccolithophores are most abundant. Here, we present measurements of annual CaCO 3 flux and quantitatively partition them amongst coccolithophore species and heterotrophic calcifiers at two sites representative of a large portion of the Subantarctic Zone. We find that coccolithophores account for a major fraction of the annual CaCO 3 export with highest contributions in waters with low algal biomass accumulations. Notably, our analysis reveals that although Emiliania huxleyi is an important vector for CaCO 3 export to the deep sea, less abundant but larger species account for most of the annual coccolithophore CaCO 3 flux. This observation contrasts with satellite remote sensing images that mostly reflect E. huxleyi blooms as a result of its higher cell abundance and detachment of its relatively small liths. It appears likely that the climate-induced migration of oceanic fronts will initially result in the poleward expansion of large coccolithophore species increasing CaCO 3 production. However, subantarctic coccolithophore populations will eventually diminish as acidification overwhelms those changes. Overall, our analysis emphasizes the need for species-centred studies to improve our ability to project future changes in phytoplankton communities and their influence on marine biogeochemical cycles. |
format |
Text |
author |
Rigual Hernández, Andrés S. Trull, Thomas W. Nodder, Scott D. Flores, José A. Bostock, Helen Abrantes, Fátima Eriksen, Ruth S. Sierro, Francisco J. Davies, Diana M. Ballegeer, Anne-Marie Fuertes, Miguel A. Northcote, Lisa C. |
spellingShingle |
Rigual Hernández, Andrés S. Trull, Thomas W. Nodder, Scott D. Flores, José A. Bostock, Helen Abrantes, Fátima Eriksen, Ruth S. Sierro, Francisco J. Davies, Diana M. Ballegeer, Anne-Marie Fuertes, Miguel A. Northcote, Lisa C. Coccolithophore biodiversity controls carbonate export in the Southern Ocean |
author_facet |
Rigual Hernández, Andrés S. Trull, Thomas W. Nodder, Scott D. Flores, José A. Bostock, Helen Abrantes, Fátima Eriksen, Ruth S. Sierro, Francisco J. Davies, Diana M. Ballegeer, Anne-Marie Fuertes, Miguel A. Northcote, Lisa C. |
author_sort |
Rigual Hernández, Andrés S. |
title |
Coccolithophore biodiversity controls carbonate export in the Southern Ocean |
title_short |
Coccolithophore biodiversity controls carbonate export in the Southern Ocean |
title_full |
Coccolithophore biodiversity controls carbonate export in the Southern Ocean |
title_fullStr |
Coccolithophore biodiversity controls carbonate export in the Southern Ocean |
title_full_unstemmed |
Coccolithophore biodiversity controls carbonate export in the Southern Ocean |
title_sort |
coccolithophore biodiversity controls carbonate export in the southern ocean |
publishDate |
2019 |
url |
https://doi.org/10.5194/bg-2019-352 https://www.biogeosciences-discuss.net/bg-2019-352/ |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-2019-352 https://www.biogeosciences-discuss.net/bg-2019-352/ |
op_doi |
https://doi.org/10.5194/bg-2019-352 |
_version_ |
1766204471655792640 |