Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton
Glacial meltwater from the western Antarctic Ice Sheet is hypothesized to be an important source of cryospheric iron, fertilizing the Southern Ocean, yet its trace-metal composition and factors that control its dispersal remain poorly constrained. Here we characterize meltwater iron sources in a hea...
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ftcopernicus:oai:publications.copernicus.org:bg93791 2023-05-15T14:02:17+02:00 Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton Forsch, Kiefer O. Hahn-Woernle, Lisa Sherrell, Robert M. Roccanova, Vincent J. Bu, Kaixuan Burdige, David Vernet, Maria Barbeau, Katherine A. 2021-12-13 application/pdf https://doi.org/10.5194/bg-18-6349-2021 https://bg.copernicus.org/articles/18/6349/2021/ eng eng doi:10.5194/bg-18-6349-2021 https://bg.copernicus.org/articles/18/6349/2021/ eISSN: 1726-4189 Text 2021 ftcopernicus https://doi.org/10.5194/bg-18-6349-2021 2021-12-20T17:22:31Z Glacial meltwater from the western Antarctic Ice Sheet is hypothesized to be an important source of cryospheric iron, fertilizing the Southern Ocean, yet its trace-metal composition and factors that control its dispersal remain poorly constrained. Here we characterize meltwater iron sources in a heavily glaciated western Antarctic Peninsula (WAP) fjord. Using dissolved and particulate ratios of manganese to iron in meltwaters, porewaters, and seawater, we show that surface glacial melt and subglacial plumes contribute to the seasonal cycle of iron and manganese within a fjord still relatively unaffected by climate-change-induced glacial retreat. Organic ligands derived from the phytoplankton bloom and the glaciers bind dissolved iron and facilitate the solubilization of particulate iron downstream. Using a numerical model, we show that buoyant plumes generated by outflow from the subglacial hydrologic system, enriched in labile particulate trace metals derived from a chemically modified crustal source, can supply iron to the fjord euphotic zone through vertical mixing. We also show that prolonged katabatic wind events enhance export of meltwater out of the fjord. Thus, we identify an important atmosphere–ice–ocean coupling intimately tied to coastal iron biogeochemistry and primary productivity along the WAP. Text Antarc* Antarctic Antarctic Peninsula Ice Sheet Southern Ocean Copernicus Publications: E-Journals Antarctic Antarctic Peninsula Southern Ocean Biogeosciences 18 23 6349 6375 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Glacial meltwater from the western Antarctic Ice Sheet is hypothesized to be an important source of cryospheric iron, fertilizing the Southern Ocean, yet its trace-metal composition and factors that control its dispersal remain poorly constrained. Here we characterize meltwater iron sources in a heavily glaciated western Antarctic Peninsula (WAP) fjord. Using dissolved and particulate ratios of manganese to iron in meltwaters, porewaters, and seawater, we show that surface glacial melt and subglacial plumes contribute to the seasonal cycle of iron and manganese within a fjord still relatively unaffected by climate-change-induced glacial retreat. Organic ligands derived from the phytoplankton bloom and the glaciers bind dissolved iron and facilitate the solubilization of particulate iron downstream. Using a numerical model, we show that buoyant plumes generated by outflow from the subglacial hydrologic system, enriched in labile particulate trace metals derived from a chemically modified crustal source, can supply iron to the fjord euphotic zone through vertical mixing. We also show that prolonged katabatic wind events enhance export of meltwater out of the fjord. Thus, we identify an important atmosphere–ice–ocean coupling intimately tied to coastal iron biogeochemistry and primary productivity along the WAP. |
format |
Text |
author |
Forsch, Kiefer O. Hahn-Woernle, Lisa Sherrell, Robert M. Roccanova, Vincent J. Bu, Kaixuan Burdige, David Vernet, Maria Barbeau, Katherine A. |
spellingShingle |
Forsch, Kiefer O. Hahn-Woernle, Lisa Sherrell, Robert M. Roccanova, Vincent J. Bu, Kaixuan Burdige, David Vernet, Maria Barbeau, Katherine A. Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton |
author_facet |
Forsch, Kiefer O. Hahn-Woernle, Lisa Sherrell, Robert M. Roccanova, Vincent J. Bu, Kaixuan Burdige, David Vernet, Maria Barbeau, Katherine A. |
author_sort |
Forsch, Kiefer O. |
title |
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton |
title_short |
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton |
title_full |
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton |
title_fullStr |
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton |
title_full_unstemmed |
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton |
title_sort |
seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal antarctic phytoplankton |
publishDate |
2021 |
url |
https://doi.org/10.5194/bg-18-6349-2021 https://bg.copernicus.org/articles/18/6349/2021/ |
geographic |
Antarctic Antarctic Peninsula Southern Ocean |
geographic_facet |
Antarctic Antarctic Peninsula Southern Ocean |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Southern Ocean |
op_source |
eISSN: 1726-4189 |
op_relation |
doi:10.5194/bg-18-6349-2021 https://bg.copernicus.org/articles/18/6349/2021/ |
op_doi |
https://doi.org/10.5194/bg-18-6349-2021 |
container_title |
Biogeosciences |
container_volume |
18 |
container_issue |
23 |
container_start_page |
6349 |
op_container_end_page |
6375 |
_version_ |
1766272477809344512 |