Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean
The high-latitude Southern Ocean phytoplankton community is shaped by the competition between Phaeocystis and silicifying diatoms, with the relative abundance of these two groups controlling primary and export production, the production of dimethylsulfide, the ratio of silicic acid and nitrate avail...
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ftcopernicus:oai:publications.copernicus.org:bgd82329 2023-05-15T18:07:34+02:00 Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean Nissen, Cara Vogt, Meike 2020-01-31 application/pdf https://doi.org/10.5194/bg-2019-488 https://www.biogeosciences-discuss.net/bg-2019-488/ eng eng doi:10.5194/bg-2019-488 https://www.biogeosciences-discuss.net/bg-2019-488/ eISSN: 1726-4189 Text 2020 ftcopernicus https://doi.org/10.5194/bg-2019-488 2020-02-03T15:42:00Z The high-latitude Southern Ocean phytoplankton community is shaped by the competition between Phaeocystis and silicifying diatoms, with the relative abundance of these two groups controlling primary and export production, the production of dimethylsulfide, the ratio of silicic acid and nitrate available in the water column, and the structure of the food web. Here, we investigate this competition using a regional physical-biogeochemical-ecological model (ROMS-BEC) configured at eddy-permitting resolution for the Southern Ocean south of 35° S. We extended ROMS-BEC by an explicit parameterization of Phaeocystis colonies, so that the model, together with the previous addition of an explicit coccolithophore type, now includes all biogeochemically relevant Southern Ocean phytoplankton types. We find that Phaeocystis contribute 46 % and 40 % to annual NPP and POC export south of 60° S, respectively, making them an important contributor to high-latitude carbon cycling. In our simulation, the relative importance of Phaeocystis and diatoms is mainly controlled by the temporal variability in temperature and iron availability. The higher light sensitivity of Phaeocystis at low irradiances promotes the succession from Phaeocystis to diatoms in more coastal areas, such as the Ross Sea. Still, differences in the biomass loss rates, such as aggregation or grazing by zooplankton, need to be considered to explain the simulated seasonal biomass evolution. Text Ross Sea Southern Ocean Copernicus Publications: E-Journals Ross Sea Southern Ocean |
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Copernicus Publications: E-Journals |
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English |
description |
The high-latitude Southern Ocean phytoplankton community is shaped by the competition between Phaeocystis and silicifying diatoms, with the relative abundance of these two groups controlling primary and export production, the production of dimethylsulfide, the ratio of silicic acid and nitrate available in the water column, and the structure of the food web. Here, we investigate this competition using a regional physical-biogeochemical-ecological model (ROMS-BEC) configured at eddy-permitting resolution for the Southern Ocean south of 35° S. We extended ROMS-BEC by an explicit parameterization of Phaeocystis colonies, so that the model, together with the previous addition of an explicit coccolithophore type, now includes all biogeochemically relevant Southern Ocean phytoplankton types. We find that Phaeocystis contribute 46 % and 40 % to annual NPP and POC export south of 60° S, respectively, making them an important contributor to high-latitude carbon cycling. In our simulation, the relative importance of Phaeocystis and diatoms is mainly controlled by the temporal variability in temperature and iron availability. The higher light sensitivity of Phaeocystis at low irradiances promotes the succession from Phaeocystis to diatoms in more coastal areas, such as the Ross Sea. Still, differences in the biomass loss rates, such as aggregation or grazing by zooplankton, need to be considered to explain the simulated seasonal biomass evolution. |
format |
Text |
author |
Nissen, Cara Vogt, Meike |
spellingShingle |
Nissen, Cara Vogt, Meike Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean |
author_facet |
Nissen, Cara Vogt, Meike |
author_sort |
Nissen, Cara |
title |
Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean |
title_short |
Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean |
title_full |
Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean |
title_fullStr |
Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean |
title_full_unstemmed |
Factors controlling the competition between Phaeocystis and diatoms in the Southern Ocean |
title_sort |
factors controlling the competition between phaeocystis and diatoms in the southern ocean |
publishDate |
2020 |
url |
https://doi.org/10.5194/bg-2019-488 https://www.biogeosciences-discuss.net/bg-2019-488/ |
geographic |
Ross Sea Southern Ocean |
geographic_facet |
Ross Sea Southern Ocean |
genre |
Ross Sea Southern Ocean |
genre_facet |
Ross Sea Southern Ocean |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-2019-488 https://www.biogeosciences-discuss.net/bg-2019-488/ |
op_doi |
https://doi.org/10.5194/bg-2019-488 |
_version_ |
1766179765028388864 |