The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients
Abstract: Hydrography and nutrient distribution in relation to plankton biomass and composition were studied during two transects (October and December) that crossed the ice-covered eastern Weddell Sea (approximately along the Greenwich Meridian) from the ice edge at 58°S to the continental margin a...
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ftawi:oai:epic.awi.de:2729 2024-09-15T17:47:04+00:00 The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients Scharek, R. Smetacek, Victor Fahrbach, Eberhard Gordon, L. I. Rohardt, Gerd Moore, S. 1994 https://epic.awi.de/id/eprint/2729/ https://hdl.handle.net/10013/epic.13313 unknown Scharek, R. , Smetacek, V. , Fahrbach, E. , Gordon, L. I. , Rohardt, G. orcid:0000-0003-0479-7638 and Moore, S. (1994) The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients , Deep-Sea Research I, 4 , pp. 1231-1250 . hdl:10013/epic.13313 EPIC3Deep-Sea Research I, 4, pp. 1231-1250 Article isiRev 1994 ftawi 2024-06-24T03:53:43Z Abstract: Hydrography and nutrient distribution in relation to plankton biomass and composition were studied during two transects (October and December) that crossed the ice-covered eastern Weddell Sea (approximately along the Greenwich Meridian) from the ice edge at 58°S to the continental margin at 70°30S in 1986. Whereas the winter situation still prevailed under the intact ice cover during the October transect, extensive melting was underway by December. Despite the very low levels of plankton biomass encountered under sea ice in late winter (as low at 0.02 µg. chlorophyll a 1-1 ), distinct differences, particularly in diatom abundance and species composition, were present between the northern eastward-flowing and southern, westward-flowing limbs of the Weddell Gyre. On the basis of species composition and physiological state of diatom assemblages, the higher biomass of the northern limb is attributed to entrainment of plankton-rich water from the ice-free Circumpolar Current rather than to in situ growth. The pelagic community characteristic of the region under the pack ice throughout the study was dominated by nanoflagellates, ciliates and heterotrophic dinoflagellates. Biomass of the latter groups ranged between 12 and 119% of that of autotrophs, and microscopic observations suggested that grazing pressure was heavy. This winter and early spring community resembled the regenerating communities of nutrient-limited waters. Break-up and melt of the ice cover in early December occurred simultaneously over an extensive area yet did not elicit biomass build-up, not even at the northern ice edge where favorable growth conditions appeared to prevail. Apparently most of the diatoms sinking into the water from the rich stocks developing in melting ice are grazed by protozoa and krill, hence do not contribute to water column blooms in this region. This situation contrasts with those reported from the western Weddell and Ross Sea ice edges where blooms of ice diatoms were observed in sharply defined melt-water zones ... Article in Journal/Newspaper Antarc* Antarctica Ross Sea Sea ice Weddell Sea Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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ftawi |
language |
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description |
Abstract: Hydrography and nutrient distribution in relation to plankton biomass and composition were studied during two transects (October and December) that crossed the ice-covered eastern Weddell Sea (approximately along the Greenwich Meridian) from the ice edge at 58°S to the continental margin at 70°30S in 1986. Whereas the winter situation still prevailed under the intact ice cover during the October transect, extensive melting was underway by December. Despite the very low levels of plankton biomass encountered under sea ice in late winter (as low at 0.02 µg. chlorophyll a 1-1 ), distinct differences, particularly in diatom abundance and species composition, were present between the northern eastward-flowing and southern, westward-flowing limbs of the Weddell Gyre. On the basis of species composition and physiological state of diatom assemblages, the higher biomass of the northern limb is attributed to entrainment of plankton-rich water from the ice-free Circumpolar Current rather than to in situ growth. The pelagic community characteristic of the region under the pack ice throughout the study was dominated by nanoflagellates, ciliates and heterotrophic dinoflagellates. Biomass of the latter groups ranged between 12 and 119% of that of autotrophs, and microscopic observations suggested that grazing pressure was heavy. This winter and early spring community resembled the regenerating communities of nutrient-limited waters. Break-up and melt of the ice cover in early December occurred simultaneously over an extensive area yet did not elicit biomass build-up, not even at the northern ice edge where favorable growth conditions appeared to prevail. Apparently most of the diatoms sinking into the water from the rich stocks developing in melting ice are grazed by protozoa and krill, hence do not contribute to water column blooms in this region. This situation contrasts with those reported from the western Weddell and Ross Sea ice edges where blooms of ice diatoms were observed in sharply defined melt-water zones ... |
format |
Article in Journal/Newspaper |
author |
Scharek, R. Smetacek, Victor Fahrbach, Eberhard Gordon, L. I. Rohardt, Gerd Moore, S. |
spellingShingle |
Scharek, R. Smetacek, Victor Fahrbach, Eberhard Gordon, L. I. Rohardt, Gerd Moore, S. The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients |
author_facet |
Scharek, R. Smetacek, Victor Fahrbach, Eberhard Gordon, L. I. Rohardt, Gerd Moore, S. |
author_sort |
Scharek, R. |
title |
The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients |
title_short |
The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients |
title_full |
The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients |
title_fullStr |
The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients |
title_full_unstemmed |
The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients |
title_sort |
transition from winter to early spring in the eastern weddell sea, antarctica: plankton biomass and composition in relation to hydrography and nutrients |
publishDate |
1994 |
url |
https://epic.awi.de/id/eprint/2729/ https://hdl.handle.net/10013/epic.13313 |
genre |
Antarc* Antarctica Ross Sea Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctica Ross Sea Sea ice Weddell Sea |
op_source |
EPIC3Deep-Sea Research I, 4, pp. 1231-1250 |
op_relation |
Scharek, R. , Smetacek, V. , Fahrbach, E. , Gordon, L. I. , Rohardt, G. orcid:0000-0003-0479-7638 and Moore, S. (1994) The transition from winter to early spring in the eastern Weddell Sea, Antarctica: Plankton biomass and composition in relation to hydrography and nutrients , Deep-Sea Research I, 4 , pp. 1231-1250 . hdl:10013/epic.13313 |
_version_ |
1810495619597336576 |