Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea
Increased sea ice melt alters vertical surface-mixing processes in Arctic seas. More melt water strengthens the stratification, but an absent ice cover also exposes the uppermost part of the water column to wind-induced mixing processes. We conducted a field study in the Barents Sea, an Arctic shelf...
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crunicaliforniap:10.1525/elementa.235 2023-12-10T09:45:00+01:00 Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea Wiedmann, Ingrid Tremblay, Jean-Éric Sundfjord, Arild Reigstad, Marit Deming, Jody W. Keister, Julie E. 2017 http://dx.doi.org/10.1525/elementa.235 http://online.ucpress.edu/elementa/article-pdf/doi/10.1525/elementa.235/472858/235-3594-1-pb.pdf en eng University of California Press http://creativecommons.org/licenses/by/4.0/ Elementa: Science of the Anthropocene volume 5 ISSN 2325-1026 Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography journal-article 2017 crunicaliforniap https://doi.org/10.1525/elementa.235 2023-11-16T18:33:41Z Increased sea ice melt alters vertical surface-mixing processes in Arctic seas. More melt water strengthens the stratification, but an absent ice cover also exposes the uppermost part of the water column to wind-induced mixing processes. We conducted a field study in the Barents Sea, an Arctic shelf sea, to examine the effects of stratification and vertical mixing processes on 1) the upward nitrate flux (into surface layers <65 m) and 2) the downward flux of particulate organic carbon (POC) to ≤200 m. In the Arctic-influenced, drift ice-covered northern Barents Sea, we found a low upward nitrate flux into the surface layers (<0.1 mmol nitrate m–2 d–1) and a moderate downward POC flux (40–200 m: 150–250 mg POC m–2 d–1) during the late phase of a peak bloom. A 1-D residence time calculation indicated that the nitrate concentration in the surface layers constantly declined. In the Atlantic-influenced, ice-free, and weakly stratified southern Barents Sea a high upward nitrate flux was found (into the surface layers ≤25 m: >5 mmol nitrate m–2 d–1) during a post bloom situation which was associated with a high downward POC flux (40–120 m: 260–600 mg POC m–2 d–1). We suggest that strong wind events during our field study induced vertical mixing processes and triggered upwards nitrate flux, while a combination of down-mixed phytoplankton and fast-sinking mesozooplankton fecal pellets enhanced the downward POC flux. The results of this study underscore the need to further investigate the role of strong, episodic wind events on the upward nitrate and downward POC fluxes in weakly stratified regions of the Arctic that may be ice-free in future. Article in Journal/Newspaper Arctic Barents Sea Phytoplankton Sea ice University of California Press (via Crossref) Arctic Barents Sea Elem Sci Anth 5 0 43 |
institution |
Open Polar |
collection |
University of California Press (via Crossref) |
op_collection_id |
crunicaliforniap |
language |
English |
topic |
Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography |
spellingShingle |
Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography Wiedmann, Ingrid Tremblay, Jean-Éric Sundfjord, Arild Reigstad, Marit Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea |
topic_facet |
Atmospheric Science Geology Geotechnical Engineering and Engineering Geology Ecology Environmental Engineering Oceanography |
description |
Increased sea ice melt alters vertical surface-mixing processes in Arctic seas. More melt water strengthens the stratification, but an absent ice cover also exposes the uppermost part of the water column to wind-induced mixing processes. We conducted a field study in the Barents Sea, an Arctic shelf sea, to examine the effects of stratification and vertical mixing processes on 1) the upward nitrate flux (into surface layers <65 m) and 2) the downward flux of particulate organic carbon (POC) to ≤200 m. In the Arctic-influenced, drift ice-covered northern Barents Sea, we found a low upward nitrate flux into the surface layers (<0.1 mmol nitrate m–2 d–1) and a moderate downward POC flux (40–200 m: 150–250 mg POC m–2 d–1) during the late phase of a peak bloom. A 1-D residence time calculation indicated that the nitrate concentration in the surface layers constantly declined. In the Atlantic-influenced, ice-free, and weakly stratified southern Barents Sea a high upward nitrate flux was found (into the surface layers ≤25 m: >5 mmol nitrate m–2 d–1) during a post bloom situation which was associated with a high downward POC flux (40–120 m: 260–600 mg POC m–2 d–1). We suggest that strong wind events during our field study induced vertical mixing processes and triggered upwards nitrate flux, while a combination of down-mixed phytoplankton and fast-sinking mesozooplankton fecal pellets enhanced the downward POC flux. The results of this study underscore the need to further investigate the role of strong, episodic wind events on the upward nitrate and downward POC fluxes in weakly stratified regions of the Arctic that may be ice-free in future. |
author2 |
Deming, Jody W. Keister, Julie E. |
format |
Article in Journal/Newspaper |
author |
Wiedmann, Ingrid Tremblay, Jean-Éric Sundfjord, Arild Reigstad, Marit |
author_facet |
Wiedmann, Ingrid Tremblay, Jean-Éric Sundfjord, Arild Reigstad, Marit |
author_sort |
Wiedmann, Ingrid |
title |
Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea |
title_short |
Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea |
title_full |
Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea |
title_fullStr |
Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea |
title_full_unstemmed |
Upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an Arctic shelf sea |
title_sort |
upward nitrate flux and downward particulate organic carbon flux under contrasting situations of stratification and turbulent mixing in an arctic shelf sea |
publisher |
University of California Press |
publishDate |
2017 |
url |
http://dx.doi.org/10.1525/elementa.235 http://online.ucpress.edu/elementa/article-pdf/doi/10.1525/elementa.235/472858/235-3594-1-pb.pdf |
geographic |
Arctic Barents Sea |
geographic_facet |
Arctic Barents Sea |
genre |
Arctic Barents Sea Phytoplankton Sea ice |
genre_facet |
Arctic Barents Sea Phytoplankton Sea ice |
op_source |
Elementa: Science of the Anthropocene volume 5 ISSN 2325-1026 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1525/elementa.235 |
container_title |
Elem Sci Anth |
container_volume |
5 |
container_issue |
0 |
container_start_page |
43 |
_version_ |
1784888240696721408 |