Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults
The overwintering success of Euphausia superba is a key factor that dictates population size, but there is un-certainty over how they cope with the scarcity of pelagic food. Both nonfeeding strategies (reduced metabolism, lipid use, or shrinkage in size) and switching to other foods (carnivory, ice...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.549.3957 2023-05-15T13:37:32+02:00 Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults A. Atkinson B. Meyer W. Hagen K. Schmidt U. V. Bathmann The Pennsylvania State University CiteSeerX Archives application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.3957 http://www.aslo.org/lo/toc/vol_47/issue_4/0953.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.3957 http://www.aslo.org/lo/toc/vol_47/issue_4/0953.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://www.aslo.org/lo/toc/vol_47/issue_4/0953.pdf text ftciteseerx 2016-01-08T11:26:26Z The overwintering success of Euphausia superba is a key factor that dictates population size, but there is un-certainty over how they cope with the scarcity of pelagic food. Both nonfeeding strategies (reduced metabolism, lipid use, or shrinkage in size) and switching to other foods (carnivory, ice algae, or detritus) have been suggested. We examined these alternatives in the southwest Lazarev Sea in autumn (April 1999), when sea ice was forming and phytoplankton was at winter concentrations. Both juveniles and adults had a very high lipid content (36 % and 44 % of dry mass, respectively) of which.40 % was phospholipid. However, their low O: N ratios suggested that these reserves were not being used. Results from gut contents analysis and large volume incubations agreed that juveniles fed mainly on phytoplankton and adults fed on small (,3 mm) copepods. This dietary difference was supported possibly by elevated concentrations of 20: 1 and 22: 1 fatty acids in the adults. The feeding methods also confirmed that feeding rates were low compared with those in summer. Even when acclimated to high food con-centrations, clearance and ingestion rates were,30 % of summer rates. Respiration and ammonium excretion rates of freshly caught krill were 60%–80 % of those in summer and declined significantly during 18 d of starvation. These findings suggest both switch feeding and energy conservation strategies, with a trend of reduced and more carnivorous feeding with ontogeny. This points to a ‘‘compromise’ ’ strategy for postlarvae, but there are alternative Text Antarc* Antarctic Antarctic Krill Euphausia superba ice algae Lazarev Sea Sea ice Copepods Unknown Antarctic Lazarev ENVELOPE(12.917,12.917,-69.967,-69.967) Lazarev Sea ENVELOPE(7.000,7.000,-68.000,-68.000) |
institution |
Open Polar |
collection |
Unknown |
op_collection_id |
ftciteseerx |
language |
English |
description |
The overwintering success of Euphausia superba is a key factor that dictates population size, but there is un-certainty over how they cope with the scarcity of pelagic food. Both nonfeeding strategies (reduced metabolism, lipid use, or shrinkage in size) and switching to other foods (carnivory, ice algae, or detritus) have been suggested. We examined these alternatives in the southwest Lazarev Sea in autumn (April 1999), when sea ice was forming and phytoplankton was at winter concentrations. Both juveniles and adults had a very high lipid content (36 % and 44 % of dry mass, respectively) of which.40 % was phospholipid. However, their low O: N ratios suggested that these reserves were not being used. Results from gut contents analysis and large volume incubations agreed that juveniles fed mainly on phytoplankton and adults fed on small (,3 mm) copepods. This dietary difference was supported possibly by elevated concentrations of 20: 1 and 22: 1 fatty acids in the adults. The feeding methods also confirmed that feeding rates were low compared with those in summer. Even when acclimated to high food con-centrations, clearance and ingestion rates were,30 % of summer rates. Respiration and ammonium excretion rates of freshly caught krill were 60%–80 % of those in summer and declined significantly during 18 d of starvation. These findings suggest both switch feeding and energy conservation strategies, with a trend of reduced and more carnivorous feeding with ontogeny. This points to a ‘‘compromise’ ’ strategy for postlarvae, but there are alternative |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
A. Atkinson B. Meyer W. Hagen K. Schmidt U. V. Bathmann |
spellingShingle |
A. Atkinson B. Meyer W. Hagen K. Schmidt U. V. Bathmann Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults |
author_facet |
A. Atkinson B. Meyer W. Hagen K. Schmidt U. V. Bathmann |
author_sort |
A. Atkinson |
title |
Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults |
title_short |
Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults |
title_full |
Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults |
title_fullStr |
Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults |
title_full_unstemmed |
Feeding and energy budgets of Antarctic krill Euphausia superba at the onset of winter—II. Juveniles and adults |
title_sort |
feeding and energy budgets of antarctic krill euphausia superba at the onset of winter—ii. juveniles and adults |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.3957 http://www.aslo.org/lo/toc/vol_47/issue_4/0953.pdf |
long_lat |
ENVELOPE(12.917,12.917,-69.967,-69.967) ENVELOPE(7.000,7.000,-68.000,-68.000) |
geographic |
Antarctic Lazarev Lazarev Sea |
geographic_facet |
Antarctic Lazarev Lazarev Sea |
genre |
Antarc* Antarctic Antarctic Krill Euphausia superba ice algae Lazarev Sea Sea ice Copepods |
genre_facet |
Antarc* Antarctic Antarctic Krill Euphausia superba ice algae Lazarev Sea Sea ice Copepods |
op_source |
http://www.aslo.org/lo/toc/vol_47/issue_4/0953.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.3957 http://www.aslo.org/lo/toc/vol_47/issue_4/0953.pdf |
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Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766093423379480576 |