Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea
Abstract: The Scotia Sea is the site of one of the largest spring phytoplankton blooms in the Southern Ocean. Past studies suggest that shelf‐iron inputs are responsible for the high productivity in this region, but the physical mechanisms that initiate and sustain the bloom are not well understood....
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ftcdlib:oai:escholarship.org:ark:/13030/qt9tz4q3pc 2024-01-14T10:02:22+01:00 Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea Prend, Channing J Gille, Sarah T Talley, Lynne D Mitchell, B Greg Rosso, Isabella Mazloff, Matthew R 5811 - 5826 2019-08-01 application/pdf https://escholarship.org/uc/item/9tz4q3pc unknown eScholarship, University of California qt9tz4q3pc https://escholarship.org/uc/item/9tz4q3pc public Journal of Geophysical Research - Oceans, vol 124, iss 8 Earth Sciences Oceanography Life Below Water Geophysics Physical Geography and Environmental Geoscience article 2019 ftcdlib 2023-12-18T19:07:35Z Abstract: The Scotia Sea is the site of one of the largest spring phytoplankton blooms in the Southern Ocean. Past studies suggest that shelf‐iron inputs are responsible for the high productivity in this region, but the physical mechanisms that initiate and sustain the bloom are not well understood. Analysis of profiling float data from 2002 to 2017 shows that the Scotia Sea has an unusually shallow mixed‐layer depth during the transition from winter to spring, allowing the region to support a bloom earlier in the season than elsewhere in the Antarctic Circumpolar Current. We compare these results to the mixed‐layer depth in the 1/6° data‐assimilating Southern Ocean State Estimate and then use the model output to assess the physical balances governing mixed‐layer variability in the region. Results indicate the importance of lateral advection of Weddell Sea surface waters in setting the stratification. A Lagrangian particle release experiment run backward in time suggests that Weddell outflow constitutes 10% of the waters in the upper 200 m of the water column in the bloom region. This dense Weddell water subducts below the surface waters in the Scotia Sea, establishing a sharp subsurface density contrast that cannot be overcome by wintertime convection. Profiling float trajectories are consistent with the formation of Taylor columns over the region's complex bathymetry, which may also contribute to the unique stratification. Furthermore, biogeochemical measurements from 2016 and 2017 bloom events suggest that vertical exchange associated with this Taylor column enhances productivity by delivering nutrients to the euphotic zone. Article in Journal/Newspaper Antarc* Antarctic Scotia Sea Southern Ocean Weddell Sea University of California: eScholarship Antarctic Southern Ocean The Antarctic Weddell Sea Scotia Sea Weddell |
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Open Polar |
collection |
University of California: eScholarship |
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topic |
Earth Sciences Oceanography Life Below Water Geophysics Physical Geography and Environmental Geoscience |
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Earth Sciences Oceanography Life Below Water Geophysics Physical Geography and Environmental Geoscience Prend, Channing J Gille, Sarah T Talley, Lynne D Mitchell, B Greg Rosso, Isabella Mazloff, Matthew R Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea |
topic_facet |
Earth Sciences Oceanography Life Below Water Geophysics Physical Geography and Environmental Geoscience |
description |
Abstract: The Scotia Sea is the site of one of the largest spring phytoplankton blooms in the Southern Ocean. Past studies suggest that shelf‐iron inputs are responsible for the high productivity in this region, but the physical mechanisms that initiate and sustain the bloom are not well understood. Analysis of profiling float data from 2002 to 2017 shows that the Scotia Sea has an unusually shallow mixed‐layer depth during the transition from winter to spring, allowing the region to support a bloom earlier in the season than elsewhere in the Antarctic Circumpolar Current. We compare these results to the mixed‐layer depth in the 1/6° data‐assimilating Southern Ocean State Estimate and then use the model output to assess the physical balances governing mixed‐layer variability in the region. Results indicate the importance of lateral advection of Weddell Sea surface waters in setting the stratification. A Lagrangian particle release experiment run backward in time suggests that Weddell outflow constitutes 10% of the waters in the upper 200 m of the water column in the bloom region. This dense Weddell water subducts below the surface waters in the Scotia Sea, establishing a sharp subsurface density contrast that cannot be overcome by wintertime convection. Profiling float trajectories are consistent with the formation of Taylor columns over the region's complex bathymetry, which may also contribute to the unique stratification. Furthermore, biogeochemical measurements from 2016 and 2017 bloom events suggest that vertical exchange associated with this Taylor column enhances productivity by delivering nutrients to the euphotic zone. |
format |
Article in Journal/Newspaper |
author |
Prend, Channing J Gille, Sarah T Talley, Lynne D Mitchell, B Greg Rosso, Isabella Mazloff, Matthew R |
author_facet |
Prend, Channing J Gille, Sarah T Talley, Lynne D Mitchell, B Greg Rosso, Isabella Mazloff, Matthew R |
author_sort |
Prend, Channing J |
title |
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea |
title_short |
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea |
title_full |
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea |
title_fullStr |
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea |
title_full_unstemmed |
Physical Drivers of Phytoplankton Bloom Initiation in the Southern Ocean's Scotia Sea |
title_sort |
physical drivers of phytoplankton bloom initiation in the southern ocean's scotia sea |
publisher |
eScholarship, University of California |
publishDate |
2019 |
url |
https://escholarship.org/uc/item/9tz4q3pc |
op_coverage |
5811 - 5826 |
geographic |
Antarctic Southern Ocean The Antarctic Weddell Sea Scotia Sea Weddell |
geographic_facet |
Antarctic Southern Ocean The Antarctic Weddell Sea Scotia Sea Weddell |
genre |
Antarc* Antarctic Scotia Sea Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctic Scotia Sea Southern Ocean Weddell Sea |
op_source |
Journal of Geophysical Research - Oceans, vol 124, iss 8 |
op_relation |
qt9tz4q3pc https://escholarship.org/uc/item/9tz4q3pc |
op_rights |
public |
_version_ |
1788057349232001024 |