Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data
<p>Some of the highest rates of primary production across the Southern Ocean occur in the seasonal ice zone (SIZ), making this a prominent area of importance for both local ecosystems and the global carbon cycle. There, the annual advance and retreat of ice impacts light and nutrient availabil...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2024-04-01
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| Series: | Ocean Science |
| Online Access: | https://os.copernicus.org/articles/20/475/2024/os-20-475-2024.pdf |
| _version_ | 1797224024682528768 |
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| author | C. C. Douglas C. C. Douglas N. Briggs P. Brown G. MacGilchrist G. MacGilchrist A. Naveira Garabato |
| author_facet | C. C. Douglas C. C. Douglas N. Briggs P. Brown G. MacGilchrist G. MacGilchrist A. Naveira Garabato |
| author_sort | C. C. Douglas |
| collection | DOAJ |
| description | <p>Some of the highest rates of primary production across the Southern Ocean occur in the seasonal ice zone (SIZ), making this a prominent area of importance for both local ecosystems and the global carbon cycle. There, the annual advance and retreat of ice impacts light and nutrient availability, as well as the circulation and stratification, thereby imposing a dominant control on phytoplankton growth. In this study, the drivers of variability in phytoplankton growth between 2002–2020 in the Weddell Gyre SIZ were assessed using satellite net primary production (NPP) products alongside chlorophyll-<span class="inline-formula"><i>a</i></span> and particulate organic carbon (POC) data from autonomous biogeochemical floats. Although the highest daily rates of NPP are consistently observed in the continental shelf region (water depths shallower than 2000 m), the open-ocean region's larger size and longer ice-free season mean that it dominates biological carbon uptake within the Weddell Gyre, accounting for 93 %–96 % of the basin's total annual NPP. Variability in the summer maximum ice-free area is the strongest predictor of inter-annual variability in total NPP across the Weddell Gyre, with greater ice-free area resulting in greater annual NPP, explaining nearly half of the variance (<span class="inline-formula"><i>R</i><sup>2</sup>=42</span> %). In the shelf region, the return of sea ice cover controls the end of the productive season. In the open ocean, however, both satellite NPP and float data show that a decline in NPP occurs before the end of the ice-free season (<span class="inline-formula">∼</span> 80 to 130 d after sea ice retreat). Evidence of concurrent increases in float-observed chlorophyll-<span class="inline-formula"><i>a</i></span> and POC suggest that later in the summer season additional factors such as micro-nutrient availability or top-down controls (e.g. grazing) could be limiting NPP. These results indicate that in a warmer and more ice-free Weddell Gyre, notwithstanding compensating changes in nutrient supply, NPP is likely to be enhanced only up to a certain limit of ice-free days.</p> |
| first_indexed | 2024-04-24T13:46:33Z |
| format | Article |
| id | doaj.art-d4f3aa4ecb4c4ff88654d96e17831d17 |
| institution | Directory Open Access Journal |
| issn | 1812-0784 1812-0792 |
| language | English |
| last_indexed | 2024-04-24T13:46:33Z |
| publishDate | 2024-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj.art-d4f3aa4ecb4c4ff88654d96e17831d172024-04-04T06:23:24ZengCopernicus PublicationsOcean Science1812-07841812-07922024-04-012047549710.5194/os-20-475-2024Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float dataC. C. Douglas0C. C. Douglas1N. Briggs2P. Brown3G. MacGilchrist4G. MacGilchrist5A. Naveira Garabato6Ocean and Earth Science, University of Southampton, Southampton, UKOcean BioGeosciences, National Oceanography Centre, Southampton, UKOcean BioGeosciences, National Oceanography Centre, Southampton, UKOcean BioGeosciences, National Oceanography Centre, Southampton, UKAtmospheric and Oceanic Science, Princeton University, Princeton, NJ, USASchool of Earth and Environmental Sciences, University of St Andrews, St Andrews, UKOcean and Earth Science, University of Southampton, Southampton, UK<p>Some of the highest rates of primary production across the Southern Ocean occur in the seasonal ice zone (SIZ), making this a prominent area of importance for both local ecosystems and the global carbon cycle. There, the annual advance and retreat of ice impacts light and nutrient availability, as well as the circulation and stratification, thereby imposing a dominant control on phytoplankton growth. In this study, the drivers of variability in phytoplankton growth between 2002–2020 in the Weddell Gyre SIZ were assessed using satellite net primary production (NPP) products alongside chlorophyll-<span class="inline-formula"><i>a</i></span> and particulate organic carbon (POC) data from autonomous biogeochemical floats. Although the highest daily rates of NPP are consistently observed in the continental shelf region (water depths shallower than 2000 m), the open-ocean region's larger size and longer ice-free season mean that it dominates biological carbon uptake within the Weddell Gyre, accounting for 93 %–96 % of the basin's total annual NPP. Variability in the summer maximum ice-free area is the strongest predictor of inter-annual variability in total NPP across the Weddell Gyre, with greater ice-free area resulting in greater annual NPP, explaining nearly half of the variance (<span class="inline-formula"><i>R</i><sup>2</sup>=42</span> %). In the shelf region, the return of sea ice cover controls the end of the productive season. In the open ocean, however, both satellite NPP and float data show that a decline in NPP occurs before the end of the ice-free season (<span class="inline-formula">∼</span> 80 to 130 d after sea ice retreat). Evidence of concurrent increases in float-observed chlorophyll-<span class="inline-formula"><i>a</i></span> and POC suggest that later in the summer season additional factors such as micro-nutrient availability or top-down controls (e.g. grazing) could be limiting NPP. These results indicate that in a warmer and more ice-free Weddell Gyre, notwithstanding compensating changes in nutrient supply, NPP is likely to be enhanced only up to a certain limit of ice-free days.</p>https://os.copernicus.org/articles/20/475/2024/os-20-475-2024.pdf |
| spellingShingle | C. C. Douglas C. C. Douglas N. Briggs P. Brown G. MacGilchrist G. MacGilchrist A. Naveira Garabato Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data Ocean Science |
| title | Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data |
| title_full | Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data |
| title_fullStr | Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data |
| title_full_unstemmed | Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data |
| title_short | Exploring the relationship between sea ice and phytoplankton growth in the Weddell Gyre using satellite and Argo float data |
| title_sort | exploring the relationship between sea ice and phytoplankton growth in the weddell gyre using satellite and argo float data |
| url | https://os.copernicus.org/articles/20/475/2024/os-20-475-2024.pdf |
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