Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica
We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region, including a detailed characterization of its freshwater distributions. Multiple components contribute to the freshwater budget, including precipitation, sea ice melt, basal ice shelf melt, and iceberg...
Published in: | Elementa: Science of the Anthropocene |
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Online Access: | http://nora.nerc.ac.uk/id/eprint/508934/ https://nora.nerc.ac.uk/id/eprint/508934/1/journal.elementa.000065.pdf https://elementascience.org/articles/65 |
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ftnerc:oai:nora.nerc.ac.uk:508934 2023-05-15T13:23:57+02:00 Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica Randall-Goodwin, E. Meredith, M. P. Jenkins, A. Yager, P. L. Sherrell, R. M. Abrahamsen, E. P. Guerrero, R. Yuan, X. Mortlock, R. A. Gavahan, K. Alderkamp, A.-C. Ducklow, H. Robertson, R. Stammerjohn, S. E. 2015-08 text http://nora.nerc.ac.uk/id/eprint/508934/ https://nora.nerc.ac.uk/id/eprint/508934/1/journal.elementa.000065.pdf https://elementascience.org/articles/65 en eng BioOne https://nora.nerc.ac.uk/id/eprint/508934/1/journal.elementa.000065.pdf Randall-Goodwin, E.; Meredith, M. P. orcid:0000-0002-7342-7756 Jenkins, A. orcid:0000-0002-9117-0616 Yager, P. L.; Sherrell, R. M.; Abrahamsen, E. P. orcid:0000-0001-5924-5350 Guerrero, R.; Yuan, X.; Mortlock, R. A.; Gavahan, K.; Alderkamp, A.-C.; Ducklow, H.; Robertson, R.; Stammerjohn, S. E. 2015 Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica. Elementa: Science of the Anthropocene, 3, 000065. https://doi.org/10.12952/journal.elementa.000065 <https://doi.org/10.12952/journal.elementa.000065> cc_by CC-BY Publication - Article PeerReviewed 2015 ftnerc https://doi.org/10.12952/journal.elementa.000065 2023-02-04T19:40:35Z We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region, including a detailed characterization of its freshwater distributions. Multiple components contribute to the freshwater budget, including precipitation, sea ice melt, basal ice shelf melt, and iceberg melt, from local and non-local sources. We used stable oxygen isotope ratios in seawater (δ18O) to distinguish quantitatively the contributions from sea ice and meteoric-derived sources. Meteoric fractions were high throughout the winter mixed layer (WML), with maximum values of 2–3% (±0.5%). Because the ASP region is characterized by deep WMLs, column inventories of total meteoric water were also high, ranging from 10–13 m (±2 m) adjacent to the Dotson Ice Shelf (DIS) and in the deep trough to 7–9 m (±2 m) in shallower areas. These inventories are at least twice those reported for continental shelf waters near the western Antarctic Peninsula. Sea ice melt fractions were mostly negative, indicating net (annual) sea ice formation, consistent with this area being an active polynya. Independently determined fractions of subsurface glacial meltwater (as one component of the total meteoric inventory) had maximum values of 1–2% (±0.5%), with highest and shallowest maximum values at the DIS outflow (80–90 m) and in iceberg-stirred waters (150–200 m). In addition to these upwelling sites, contributions of subsurface glacial meltwater could be traced at depth along the ~ 27.6 isopycnal, from which it mixes into the WML through various processes. Our results suggest a quasi-continuous supply of melt-laden iron-enriched seawater to the euphotic zone of the ASP and help to explain why the ASP is Antarctica’s most biologically productive polynya per unit area. Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Antarctic Peninsula Antarctica Dotson Ice Shelf Ice Shelf Iceberg* Sea ice Natural Environment Research Council: NERC Open Research Archive Antarctic Antarctic Peninsula Amundsen Sea Dotson Ice Shelf ENVELOPE(-112.367,-112.367,-74.400,-74.400) Elementa: Science of the Anthropocene 3 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
description |
We present the first densely-sampled hydrographic survey of the Amundsen Sea Polynya (ASP) region, including a detailed characterization of its freshwater distributions. Multiple components contribute to the freshwater budget, including precipitation, sea ice melt, basal ice shelf melt, and iceberg melt, from local and non-local sources. We used stable oxygen isotope ratios in seawater (δ18O) to distinguish quantitatively the contributions from sea ice and meteoric-derived sources. Meteoric fractions were high throughout the winter mixed layer (WML), with maximum values of 2–3% (±0.5%). Because the ASP region is characterized by deep WMLs, column inventories of total meteoric water were also high, ranging from 10–13 m (±2 m) adjacent to the Dotson Ice Shelf (DIS) and in the deep trough to 7–9 m (±2 m) in shallower areas. These inventories are at least twice those reported for continental shelf waters near the western Antarctic Peninsula. Sea ice melt fractions were mostly negative, indicating net (annual) sea ice formation, consistent with this area being an active polynya. Independently determined fractions of subsurface glacial meltwater (as one component of the total meteoric inventory) had maximum values of 1–2% (±0.5%), with highest and shallowest maximum values at the DIS outflow (80–90 m) and in iceberg-stirred waters (150–200 m). In addition to these upwelling sites, contributions of subsurface glacial meltwater could be traced at depth along the ~ 27.6 isopycnal, from which it mixes into the WML through various processes. Our results suggest a quasi-continuous supply of melt-laden iron-enriched seawater to the euphotic zone of the ASP and help to explain why the ASP is Antarctica’s most biologically productive polynya per unit area. |
format |
Article in Journal/Newspaper |
author |
Randall-Goodwin, E. Meredith, M. P. Jenkins, A. Yager, P. L. Sherrell, R. M. Abrahamsen, E. P. Guerrero, R. Yuan, X. Mortlock, R. A. Gavahan, K. Alderkamp, A.-C. Ducklow, H. Robertson, R. Stammerjohn, S. E. |
spellingShingle |
Randall-Goodwin, E. Meredith, M. P. Jenkins, A. Yager, P. L. Sherrell, R. M. Abrahamsen, E. P. Guerrero, R. Yuan, X. Mortlock, R. A. Gavahan, K. Alderkamp, A.-C. Ducklow, H. Robertson, R. Stammerjohn, S. E. Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica |
author_facet |
Randall-Goodwin, E. Meredith, M. P. Jenkins, A. Yager, P. L. Sherrell, R. M. Abrahamsen, E. P. Guerrero, R. Yuan, X. Mortlock, R. A. Gavahan, K. Alderkamp, A.-C. Ducklow, H. Robertson, R. Stammerjohn, S. E. |
author_sort |
Randall-Goodwin, E. |
title |
Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica |
title_short |
Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica |
title_full |
Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica |
title_fullStr |
Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica |
title_full_unstemmed |
Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica |
title_sort |
freshwater distributions and water mass structure in the amundsen sea polynya region, antarctica |
publisher |
BioOne |
publishDate |
2015 |
url |
http://nora.nerc.ac.uk/id/eprint/508934/ https://nora.nerc.ac.uk/id/eprint/508934/1/journal.elementa.000065.pdf https://elementascience.org/articles/65 |
long_lat |
ENVELOPE(-112.367,-112.367,-74.400,-74.400) |
geographic |
Antarctic Antarctic Peninsula Amundsen Sea Dotson Ice Shelf |
geographic_facet |
Antarctic Antarctic Peninsula Amundsen Sea Dotson Ice Shelf |
genre |
Amundsen Sea Antarc* Antarctic Antarctic Peninsula Antarctica Dotson Ice Shelf Ice Shelf Iceberg* Sea ice |
genre_facet |
Amundsen Sea Antarc* Antarctic Antarctic Peninsula Antarctica Dotson Ice Shelf Ice Shelf Iceberg* Sea ice |
op_relation |
https://nora.nerc.ac.uk/id/eprint/508934/1/journal.elementa.000065.pdf Randall-Goodwin, E.; Meredith, M. P. orcid:0000-0002-7342-7756 Jenkins, A. orcid:0000-0002-9117-0616 Yager, P. L.; Sherrell, R. M.; Abrahamsen, E. P. orcid:0000-0001-5924-5350 Guerrero, R.; Yuan, X.; Mortlock, R. A.; Gavahan, K.; Alderkamp, A.-C.; Ducklow, H.; Robertson, R.; Stammerjohn, S. E. 2015 Freshwater distributions and water mass structure in the Amundsen Sea Polynya region, Antarctica. Elementa: Science of the Anthropocene, 3, 000065. https://doi.org/10.12952/journal.elementa.000065 <https://doi.org/10.12952/journal.elementa.000065> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.12952/journal.elementa.000065 |
container_title |
Elementa: Science of the Anthropocene |
container_volume |
3 |
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1766376535267213312 |