Imprint of Southern Ocean mesoscale eddies on chlorophyll
Although mesoscale ocean eddies are ubiquitous in the Southern Ocean, their average regional and seasonal association with phytoplankton has not been quantified systematically yet. To this end, we identify over 100 000 mesoscale eddies with diameters of 50 km and more in the Southern Ocean and deter...
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ftcopernicus:oai:publications.copernicus.org:bg66609 2023-05-15T13:35:06+02:00 Imprint of Southern Ocean mesoscale eddies on chlorophyll Frenger, Ivy Münnich, Matthias Gruber, Nicolas 2019-01-21 application/pdf https://doi.org/10.5194/bg-15-4781-2018 https://www.biogeosciences.net/15/4781/2018/ eng eng doi:10.5194/bg-15-4781-2018 https://www.biogeosciences.net/15/4781/2018/ eISSN: 1726-4189 Text 2019 ftcopernicus https://doi.org/10.5194/bg-15-4781-2018 2019-12-24T09:50:00Z Although mesoscale ocean eddies are ubiquitous in the Southern Ocean, their average regional and seasonal association with phytoplankton has not been quantified systematically yet. To this end, we identify over 100 000 mesoscale eddies with diameters of 50 km and more in the Southern Ocean and determine the associated phytoplankton biomass anomalies using satellite-based chlorophyll- a (Chl) as a proxy. The mean Chl anomalies, δ Chl, associated with these eddies, comprising the upper echelon of the oceanic mesoscale, exceed ±10 % over wide regions. The structure of these anomalies is largely zonal, with cyclonic, thermocline lifted, eddies having positive anomalies in the subtropical waters north of the Antarctic Circumpolar Current (ACC) and negative anomalies along its main flow path. The pattern is similar, but reversed for anticyclonic, thermocline deepened eddies. The seasonality of δ Chl is weak in subtropical waters, but pronounced along the ACC, featuring a seasonal sign switch. The spatial structure and seasonality of the mesoscale δ Chl can be explained largely by lateral advection, especially local eddy-stirring. A prominent exception is the ACC region in winter, where δ Chl is consistent with a modulation of phytoplankton light exposure caused by an eddy-induced modification of the mixed layer depth. The clear impact of mesoscale eddies on phytoplankton may implicate a downstream effect on Southern Ocean biogeochemical properties, such as mode water nutrient contents. Text Antarc* Antarctic Southern Ocean Copernicus Publications: E-Journals Antarctic Southern Ocean The Antarctic Biogeosciences 15 15 4781 4798 |
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Copernicus Publications: E-Journals |
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English |
description |
Although mesoscale ocean eddies are ubiquitous in the Southern Ocean, their average regional and seasonal association with phytoplankton has not been quantified systematically yet. To this end, we identify over 100 000 mesoscale eddies with diameters of 50 km and more in the Southern Ocean and determine the associated phytoplankton biomass anomalies using satellite-based chlorophyll- a (Chl) as a proxy. The mean Chl anomalies, δ Chl, associated with these eddies, comprising the upper echelon of the oceanic mesoscale, exceed ±10 % over wide regions. The structure of these anomalies is largely zonal, with cyclonic, thermocline lifted, eddies having positive anomalies in the subtropical waters north of the Antarctic Circumpolar Current (ACC) and negative anomalies along its main flow path. The pattern is similar, but reversed for anticyclonic, thermocline deepened eddies. The seasonality of δ Chl is weak in subtropical waters, but pronounced along the ACC, featuring a seasonal sign switch. The spatial structure and seasonality of the mesoscale δ Chl can be explained largely by lateral advection, especially local eddy-stirring. A prominent exception is the ACC region in winter, where δ Chl is consistent with a modulation of phytoplankton light exposure caused by an eddy-induced modification of the mixed layer depth. The clear impact of mesoscale eddies on phytoplankton may implicate a downstream effect on Southern Ocean biogeochemical properties, such as mode water nutrient contents. |
format |
Text |
author |
Frenger, Ivy Münnich, Matthias Gruber, Nicolas |
spellingShingle |
Frenger, Ivy Münnich, Matthias Gruber, Nicolas Imprint of Southern Ocean mesoscale eddies on chlorophyll |
author_facet |
Frenger, Ivy Münnich, Matthias Gruber, Nicolas |
author_sort |
Frenger, Ivy |
title |
Imprint of Southern Ocean mesoscale eddies on chlorophyll |
title_short |
Imprint of Southern Ocean mesoscale eddies on chlorophyll |
title_full |
Imprint of Southern Ocean mesoscale eddies on chlorophyll |
title_fullStr |
Imprint of Southern Ocean mesoscale eddies on chlorophyll |
title_full_unstemmed |
Imprint of Southern Ocean mesoscale eddies on chlorophyll |
title_sort |
imprint of southern ocean mesoscale eddies on chlorophyll |
publishDate |
2019 |
url |
https://doi.org/10.5194/bg-15-4781-2018 https://www.biogeosciences.net/15/4781/2018/ |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-15-4781-2018 https://www.biogeosciences.net/15/4781/2018/ |
op_doi |
https://doi.org/10.5194/bg-15-4781-2018 |
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Biogeosciences |
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15 |
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15 |
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4781 |
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4798 |
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1766060951949279232 |