Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas
Over the Ross Sea shelf, annual primary production is limited by dissolved iron (DFe) supply. Here, a major source of DFe to surface waters is thought to be vertical resupply from the benthos, which is assumed most prevalent during winter months when katabatic winds drive sea ice formation and conve...
Published in: | Journal of Geophysical Research: Oceans |
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ftpubmed:oai:pubmedcentral.nih.gov:9788290 2023-05-15T13:58:38+02:00 Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas Sedwick, P. N. Sohst, B. M. O’Hara, C. Stammerjohn, S. E. Loose, B. Dinniman, M. S. Buck, N. J. Resing, J. A. Ackley, S. F. 2022-10-17 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788290/ https://doi.org/10.1029/2022JC018999 en eng John Wiley and Sons Inc. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788290/ http://dx.doi.org/10.1029/2022JC018999 © 2022. The Authors. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ (https://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. CC-BY-NC-ND J Geophys Res Oceans Research Article Text 2022 ftpubmed https://doi.org/10.1029/2022JC018999 2023-01-01T01:34:54Z Over the Ross Sea shelf, annual primary production is limited by dissolved iron (DFe) supply. Here, a major source of DFe to surface waters is thought to be vertical resupply from the benthos, which is assumed most prevalent during winter months when katabatic winds drive sea ice formation and convective overturn in coastal polynyas, although the impact of these processes on water‐column DFe distributions has not been previously documented. We collected hydrographic data and water‐column samples for trace metals analysis in the Terra Nova Bay and Ross Ice Shelf polynyas during April–May 2017 (late austral fall). In the Terra Nova Bay polynya, we observed intense katabatic wind events, and surface mixed layer depths varied from ∼250 to ∼600 m over lateral distances <10 km; there vertical mixing was just starting to excavate the dense, iron‐rich Shelf Waters, and there was also evidence of DFe inputs at shallower depths in the water column. In the Ross Ice Shelf polynya, wind speeds were lower, mixed layers were <300 m deep, and DFe distributions were similar to previous, late‐summer observations, with concentrations elevated near the seafloor. Corresponding measurements of dissolved manganese and zinc, and particulate iron, manganese, and aluminum, suggest that deep DFe maxima and some mid‐depth DFe maxima primarily reflect sedimentary inputs, rather than remineralization. Our data and model simulations imply that vertical resupply of DFe in the Ross Sea occurs mainly during mid‐late winter, and may be particularly sensitive to changes in the timing and extent of sea ice production. Text Antarc* Antarctic Ice Shelf Ross Ice Shelf Ross Sea Sea ice PubMed Central (PMC) Antarctic Austral Ross Ice Shelf Ross Sea Terra Nova Bay The Antarctic Journal of Geophysical Research: Oceans 127 10 |
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English |
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Research Article |
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Research Article Sedwick, P. N. Sohst, B. M. O’Hara, C. Stammerjohn, S. E. Loose, B. Dinniman, M. S. Buck, N. J. Resing, J. A. Ackley, S. F. Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas |
topic_facet |
Research Article |
description |
Over the Ross Sea shelf, annual primary production is limited by dissolved iron (DFe) supply. Here, a major source of DFe to surface waters is thought to be vertical resupply from the benthos, which is assumed most prevalent during winter months when katabatic winds drive sea ice formation and convective overturn in coastal polynyas, although the impact of these processes on water‐column DFe distributions has not been previously documented. We collected hydrographic data and water‐column samples for trace metals analysis in the Terra Nova Bay and Ross Ice Shelf polynyas during April–May 2017 (late austral fall). In the Terra Nova Bay polynya, we observed intense katabatic wind events, and surface mixed layer depths varied from ∼250 to ∼600 m over lateral distances <10 km; there vertical mixing was just starting to excavate the dense, iron‐rich Shelf Waters, and there was also evidence of DFe inputs at shallower depths in the water column. In the Ross Ice Shelf polynya, wind speeds were lower, mixed layers were <300 m deep, and DFe distributions were similar to previous, late‐summer observations, with concentrations elevated near the seafloor. Corresponding measurements of dissolved manganese and zinc, and particulate iron, manganese, and aluminum, suggest that deep DFe maxima and some mid‐depth DFe maxima primarily reflect sedimentary inputs, rather than remineralization. Our data and model simulations imply that vertical resupply of DFe in the Ross Sea occurs mainly during mid‐late winter, and may be particularly sensitive to changes in the timing and extent of sea ice production. |
format |
Text |
author |
Sedwick, P. N. Sohst, B. M. O’Hara, C. Stammerjohn, S. E. Loose, B. Dinniman, M. S. Buck, N. J. Resing, J. A. Ackley, S. F. |
author_facet |
Sedwick, P. N. Sohst, B. M. O’Hara, C. Stammerjohn, S. E. Loose, B. Dinniman, M. S. Buck, N. J. Resing, J. A. Ackley, S. F. |
author_sort |
Sedwick, P. N. |
title |
Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas |
title_short |
Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas |
title_full |
Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas |
title_fullStr |
Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas |
title_full_unstemmed |
Seasonal Dynamics of Dissolved Iron on the Antarctic Continental Shelf: Late‐Fall Observations From the Terra Nova Bay and Ross Ice Shelf Polynyas |
title_sort |
seasonal dynamics of dissolved iron on the antarctic continental shelf: late‐fall observations from the terra nova bay and ross ice shelf polynyas |
publisher |
John Wiley and Sons Inc. |
publishDate |
2022 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788290/ https://doi.org/10.1029/2022JC018999 |
geographic |
Antarctic Austral Ross Ice Shelf Ross Sea Terra Nova Bay The Antarctic |
geographic_facet |
Antarctic Austral Ross Ice Shelf Ross Sea Terra Nova Bay The Antarctic |
genre |
Antarc* Antarctic Ice Shelf Ross Ice Shelf Ross Sea Sea ice |
genre_facet |
Antarc* Antarctic Ice Shelf Ross Ice Shelf Ross Sea Sea ice |
op_source |
J Geophys Res Oceans |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9788290/ http://dx.doi.org/10.1029/2022JC018999 |
op_rights |
© 2022. The Authors. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ (https://creativecommons.org/licenses/by-nc-nd/4.0/) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1029/2022JC018999 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
127 |
container_issue |
10 |
_version_ |
1766266989577240576 |