Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997
The summer of 1997 was characterized by unusually large amounts of pack ice in the southeastern Weddell Sea, and less than 10% of the area that is commonly ice-free in summer was open. A modest phytoplankton bloom developed in the upper mixed layer in the northernmost area (72°S). The bloom peaked i...
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Cambridge University Press (CUP)
2002
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Online Access: | http://dx.doi.org/10.1017/s095410200200007x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095410200200007X |
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crcambridgeupr:10.1017/s095410200200007x 2024-10-13T14:03:00+00:00 Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 HEGSETH, ELSE N. VON QUILLFELDT, CECILIE H. 2002 http://dx.doi.org/10.1017/s095410200200007x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095410200200007X en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Antarctic Science volume 14, issue 3, page 231-243 ISSN 0954-1020 1365-2079 journal-article 2002 crcambridgeupr https://doi.org/10.1017/s095410200200007x 2024-09-18T04:03:47Z The summer of 1997 was characterized by unusually large amounts of pack ice in the southeastern Weddell Sea, and less than 10% of the area that is commonly ice-free in summer was open. A modest phytoplankton bloom developed in the upper mixed layer in the northernmost area (72°S). The bloom peaked in mid-February with max chlorophyll concentrations of 1.5 μg l −1 , and integrated stocks of 55–60 mg m −2 . Autotrophic flagellates dominated the biomass (80–90% of the chlorophyll) at first, while diatoms increased relative to flagellates during the bloom. Nutrient deficits, however, indicated that a much larger biomass was produced than was observed. Freezing starting after mid-February probably terminated the bloom, resulting in a pelagic growth season limited in time (less than two months) and space. The sea ice had a distinct brown layer of algae, usually at 1–2 m depth, with average chlorophyll biomass of 10.3 mg m −2 . The ice cover exhibited a substantial amount of ridges, with ice algae growing in cavities and other structures, but with lower biomass than in the bands. Ice algae were also found growing on the lower 2 m of the ice shelf (visible at low tide). The overall growth season in the ice lasted several months, and ice algal production may have exceeded pelagic production in the Weddell Sea during the growth season of 1997. Pennate diatoms, like Fragilariopsis curta and F. cylindrus , dominated both in ice and in open water above the pycnocline, while Phaeocystis antarctica dominated in deeper layers and in crack pools. Euphausiids, particularly young stages, were frequently observed grazing on ice algae in ridges and on all sides of the floes, (confirmed by the gut content). Ice algae would thus have served as an ample food supply for the krill in the summer of 1997. Article in Journal/Newspaper Antarc* Antarctic Science Antarctica ice algae Ice Shelf Sea ice Weddell Sea Cambridge University Press Weddell Weddell Sea Antarctic Science 14 3 231 243 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
The summer of 1997 was characterized by unusually large amounts of pack ice in the southeastern Weddell Sea, and less than 10% of the area that is commonly ice-free in summer was open. A modest phytoplankton bloom developed in the upper mixed layer in the northernmost area (72°S). The bloom peaked in mid-February with max chlorophyll concentrations of 1.5 μg l −1 , and integrated stocks of 55–60 mg m −2 . Autotrophic flagellates dominated the biomass (80–90% of the chlorophyll) at first, while diatoms increased relative to flagellates during the bloom. Nutrient deficits, however, indicated that a much larger biomass was produced than was observed. Freezing starting after mid-February probably terminated the bloom, resulting in a pelagic growth season limited in time (less than two months) and space. The sea ice had a distinct brown layer of algae, usually at 1–2 m depth, with average chlorophyll biomass of 10.3 mg m −2 . The ice cover exhibited a substantial amount of ridges, with ice algae growing in cavities and other structures, but with lower biomass than in the bands. Ice algae were also found growing on the lower 2 m of the ice shelf (visible at low tide). The overall growth season in the ice lasted several months, and ice algal production may have exceeded pelagic production in the Weddell Sea during the growth season of 1997. Pennate diatoms, like Fragilariopsis curta and F. cylindrus , dominated both in ice and in open water above the pycnocline, while Phaeocystis antarctica dominated in deeper layers and in crack pools. Euphausiids, particularly young stages, were frequently observed grazing on ice algae in ridges and on all sides of the floes, (confirmed by the gut content). Ice algae would thus have served as an ample food supply for the krill in the summer of 1997. |
format |
Article in Journal/Newspaper |
author |
HEGSETH, ELSE N. VON QUILLFELDT, CECILIE H. |
spellingShingle |
HEGSETH, ELSE N. VON QUILLFELDT, CECILIE H. Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 |
author_facet |
HEGSETH, ELSE N. VON QUILLFELDT, CECILIE H. |
author_sort |
HEGSETH, ELSE N. |
title |
Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 |
title_short |
Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 |
title_full |
Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 |
title_fullStr |
Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 |
title_full_unstemmed |
Low phytoplankton biomass and ice algal blooms in the Weddell Sea during the ice-filled summer of 1997 |
title_sort |
low phytoplankton biomass and ice algal blooms in the weddell sea during the ice-filled summer of 1997 |
publisher |
Cambridge University Press (CUP) |
publishDate |
2002 |
url |
http://dx.doi.org/10.1017/s095410200200007x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S095410200200007X |
geographic |
Weddell Weddell Sea |
geographic_facet |
Weddell Weddell Sea |
genre |
Antarc* Antarctic Science Antarctica ice algae Ice Shelf Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctic Science Antarctica ice algae Ice Shelf Sea ice Weddell Sea |
op_source |
Antarctic Science volume 14, issue 3, page 231-243 ISSN 0954-1020 1365-2079 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s095410200200007x |
container_title |
Antarctic Science |
container_volume |
14 |
container_issue |
3 |
container_start_page |
231 |
op_container_end_page |
243 |
_version_ |
1812819444847607808 |