Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer
Despite being the largest High Nitrate Low Chlorophyll (HNLC) region, the Southern Ocean sustains phytoplankton blooms through the summer, when presumably there is sufficient light, but nutrients in the euphotic zone have been depleted. Physical processes that can potentially supply nutrients from s...
Published in: | Journal of Geophysical Research: Oceans |
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Online Access: | https://escholarship.org/uc/item/5jh507gs https://escholarship.org/content/qt5jh507gs/qt5jh507gs.pdf https://doi.org/10.1002/2014jc010203 |
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ftcdlib:oai:escholarship.org:ark:/13030/qt5jh507gs 2024-09-15T18:37:01+00:00 Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer Carranza, Magdalena M Gille, Sarah T 304 - 323 2015-01-01 application/pdf https://escholarship.org/uc/item/5jh507gs https://escholarship.org/content/qt5jh507gs/qt5jh507gs.pdf https://doi.org/10.1002/2014jc010203 unknown eScholarship, University of California qt5jh507gs https://escholarship.org/uc/item/5jh507gs https://escholarship.org/content/qt5jh507gs/qt5jh507gs.pdf doi:10.1002/2014jc010203 public Journal of Geophysical Research - Oceans, vol 120, iss 1 Southern Ocean summer phytoplankton blooms atmospheric forcing mixed-layer depth dynamics wind-driven entrainment Ekman pumping Geophysics Oceanography Physical Geography and Environmental Geoscience article 2015 ftcdlib https://doi.org/10.1002/2014jc010203 2024-06-28T06:28:20Z Despite being the largest High Nitrate Low Chlorophyll (HNLC) region, the Southern Ocean sustains phytoplankton blooms through the summer, when presumably there is sufficient light, but nutrients in the euphotic zone have been depleted. Physical processes that can potentially supply nutrients from subsurface waters to the euphotic zone, and promote phytoplankton growth in the summer, have not been fully explored at the large scale. By means of a correlation analysis, this study combines high-resolution satellite observations of ocean color, winds and sea surface temperature, surface heat fluxes from reanalysis and Argo mixed-layer depth (MLD) estimates to explore the role of the atmospheric forcing (i.e., winds and surface heat fluxes) on upper ocean processes that may help sustain high satellite chlorophyll-a (Chl-a) through the summer. Two physical processes that can supply nutrients to the euphotic zone are: MLD deepening, caused by wind-mixing and/or surface cooling, and Ekman pumping driven by the wind stress curl. We find that high winds correlate with high Chl-a over broad open ocean areas, suggesting that transient MLD deepening through wind-mixing (i.e., wind-driven entrainment) helps sustain high Chl-a. Wind-driven entrainment plays a dominant role on time scales associated with atmospheric synoptic storms (i.e., <10 days) and has a larger influence on surface Chl-a than storm scale local Ekman pumping. Based on our analysis of statistically significant correlation patterns, we identify regions in the Southern Ocean where wind-induced entrainment may play a role in sustaining summer phytoplankton blooms. Article in Journal/Newspaper Southern Ocean University of California: eScholarship Journal of Geophysical Research: Oceans 120 1 304 323 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Southern Ocean summer phytoplankton blooms atmospheric forcing mixed-layer depth dynamics wind-driven entrainment Ekman pumping Geophysics Oceanography Physical Geography and Environmental Geoscience |
spellingShingle |
Southern Ocean summer phytoplankton blooms atmospheric forcing mixed-layer depth dynamics wind-driven entrainment Ekman pumping Geophysics Oceanography Physical Geography and Environmental Geoscience Carranza, Magdalena M Gille, Sarah T Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
topic_facet |
Southern Ocean summer phytoplankton blooms atmospheric forcing mixed-layer depth dynamics wind-driven entrainment Ekman pumping Geophysics Oceanography Physical Geography and Environmental Geoscience |
description |
Despite being the largest High Nitrate Low Chlorophyll (HNLC) region, the Southern Ocean sustains phytoplankton blooms through the summer, when presumably there is sufficient light, but nutrients in the euphotic zone have been depleted. Physical processes that can potentially supply nutrients from subsurface waters to the euphotic zone, and promote phytoplankton growth in the summer, have not been fully explored at the large scale. By means of a correlation analysis, this study combines high-resolution satellite observations of ocean color, winds and sea surface temperature, surface heat fluxes from reanalysis and Argo mixed-layer depth (MLD) estimates to explore the role of the atmospheric forcing (i.e., winds and surface heat fluxes) on upper ocean processes that may help sustain high satellite chlorophyll-a (Chl-a) through the summer. Two physical processes that can supply nutrients to the euphotic zone are: MLD deepening, caused by wind-mixing and/or surface cooling, and Ekman pumping driven by the wind stress curl. We find that high winds correlate with high Chl-a over broad open ocean areas, suggesting that transient MLD deepening through wind-mixing (i.e., wind-driven entrainment) helps sustain high Chl-a. Wind-driven entrainment plays a dominant role on time scales associated with atmospheric synoptic storms (i.e., <10 days) and has a larger influence on surface Chl-a than storm scale local Ekman pumping. Based on our analysis of statistically significant correlation patterns, we identify regions in the Southern Ocean where wind-induced entrainment may play a role in sustaining summer phytoplankton blooms. |
format |
Article in Journal/Newspaper |
author |
Carranza, Magdalena M Gille, Sarah T |
author_facet |
Carranza, Magdalena M Gille, Sarah T |
author_sort |
Carranza, Magdalena M |
title |
Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
title_short |
Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
title_full |
Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
title_fullStr |
Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
title_full_unstemmed |
Southern Ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
title_sort |
southern ocean wind‐driven entrainment enhances satellite chlorophyll‐a through the summer |
publisher |
eScholarship, University of California |
publishDate |
2015 |
url |
https://escholarship.org/uc/item/5jh507gs https://escholarship.org/content/qt5jh507gs/qt5jh507gs.pdf https://doi.org/10.1002/2014jc010203 |
op_coverage |
304 - 323 |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
Journal of Geophysical Research - Oceans, vol 120, iss 1 |
op_relation |
qt5jh507gs https://escholarship.org/uc/item/5jh507gs https://escholarship.org/content/qt5jh507gs/qt5jh507gs.pdf doi:10.1002/2014jc010203 |
op_rights |
public |
op_doi |
https://doi.org/10.1002/2014jc010203 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
120 |
container_issue |
1 |
container_start_page |
304 |
op_container_end_page |
323 |
_version_ |
1810481146728808448 |