Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach
The use of stable isotopes to study food webs has increased rapidly, but there are still some uncertainties in their application. We examined the delta(15)N and delta(13)C values of Antarctic euphausiids and copepods from the Polar Front, Lazarev Sea, and Marguerite Bay against their foodweb baselin...
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AMER SOC LIMNOLOGY OCEANOGRAPHY
2003
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ftnerc:oai:nora.nerc.ac.uk:10200 2023-05-15T13:45:10+02:00 Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach Schmidt, K. Atkinson, A. Stubing, D. McClelland, J.W. Montoya, J.P. Voss, M. 2003 http://nora.nerc.ac.uk/id/eprint/10200/ unknown AMER SOC LIMNOLOGY OCEANOGRAPHY Schmidt, K.; Atkinson, A.; Stubing, D.; McClelland, J.W.; Montoya, J.P.; Voss, M. 2003 Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach. Limnology and Oceanography, 48 (1). 277-289. Marine Sciences Biology and Microbiology Ecology and Environment Publication - Article PeerReviewed 2003 ftnerc 2023-02-04T19:26:36Z The use of stable isotopes to study food webs has increased rapidly, but there are still some uncertainties in their application. We examined the delta(15)N and delta(13)C values of Antarctic euphausiids and copepods from the Polar Front, Lazarev Sea, and Marguerite Bay against their foodweb baseline of particulate organic matter (POM). Interpretations of trophic level were helped by comparison with other approaches and by calibration experiments with Euphausia superba fed known diets: Results for well-known mesozooplankters (e.g., Calanoides acutus and Metridia gerlachei) were internally consistent and corresponded to those derived from independent methods. This gave confidence in the isotope approach for copepods and probably larval euphausiids. Among the dominant yet poorly known species, it suggested mainly herbivory for Rhincalanus gigas but omnivory for Calanus simillimus and furcilia larvae of Thysanoessa spp. and Euphausia frigida. The delta(15)N values of adult copepods were up to 3parts per thousand higher than those of early copepodites, pointing to ontogenetic shifts in diet. In the Lazarev Sea in autumn, the isotopic signals of E. superba larvae suggested pelagic, mainly herbivorous, feeding rather than feeding within the ice. In contrast to the mesozooplankton, some anomalous results for postlarval krill species indicated problems with this method for micronekton. The experiments showed that postlarval E. superba did not equilibriate with a new diet within 30 d. We suggest that the slower turnover of these larger species, partly in combination with their ability to migrate, has confounded trophic effects with those of a temporally/spatially changing food-web baseline. Interpretations of food sources of micronekton could be helped by analyzing their molts or fecal pellets, which responded faster to a new diet. Article in Journal/Newspaper Antarc* Antarctic Euphausia superba Lazarev Sea Mesozooplankton Southern Ocean Copepods Natural Environment Research Council: NERC Open Research Archive Antarctic Southern Ocean Lazarev ENVELOPE(12.917,12.917,-69.967,-69.967) Marguerite ENVELOPE(141.378,141.378,-66.787,-66.787) Lazarev Sea ENVELOPE(7.000,7.000,-68.000,-68.000) Marguerite Bay ENVELOPE(-68.000,-68.000,-68.500,-68.500) |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
topic |
Marine Sciences Biology and Microbiology Ecology and Environment |
spellingShingle |
Marine Sciences Biology and Microbiology Ecology and Environment Schmidt, K. Atkinson, A. Stubing, D. McClelland, J.W. Montoya, J.P. Voss, M. Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach |
topic_facet |
Marine Sciences Biology and Microbiology Ecology and Environment |
description |
The use of stable isotopes to study food webs has increased rapidly, but there are still some uncertainties in their application. We examined the delta(15)N and delta(13)C values of Antarctic euphausiids and copepods from the Polar Front, Lazarev Sea, and Marguerite Bay against their foodweb baseline of particulate organic matter (POM). Interpretations of trophic level were helped by comparison with other approaches and by calibration experiments with Euphausia superba fed known diets: Results for well-known mesozooplankters (e.g., Calanoides acutus and Metridia gerlachei) were internally consistent and corresponded to those derived from independent methods. This gave confidence in the isotope approach for copepods and probably larval euphausiids. Among the dominant yet poorly known species, it suggested mainly herbivory for Rhincalanus gigas but omnivory for Calanus simillimus and furcilia larvae of Thysanoessa spp. and Euphausia frigida. The delta(15)N values of adult copepods were up to 3parts per thousand higher than those of early copepodites, pointing to ontogenetic shifts in diet. In the Lazarev Sea in autumn, the isotopic signals of E. superba larvae suggested pelagic, mainly herbivorous, feeding rather than feeding within the ice. In contrast to the mesozooplankton, some anomalous results for postlarval krill species indicated problems with this method for micronekton. The experiments showed that postlarval E. superba did not equilibriate with a new diet within 30 d. We suggest that the slower turnover of these larger species, partly in combination with their ability to migrate, has confounded trophic effects with those of a temporally/spatially changing food-web baseline. Interpretations of food sources of micronekton could be helped by analyzing their molts or fecal pellets, which responded faster to a new diet. |
format |
Article in Journal/Newspaper |
author |
Schmidt, K. Atkinson, A. Stubing, D. McClelland, J.W. Montoya, J.P. Voss, M. |
author_facet |
Schmidt, K. Atkinson, A. Stubing, D. McClelland, J.W. Montoya, J.P. Voss, M. |
author_sort |
Schmidt, K. |
title |
Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach |
title_short |
Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach |
title_full |
Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach |
title_fullStr |
Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach |
title_full_unstemmed |
Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach |
title_sort |
trophic relationships among southern ocean copepods and krill: some uses and limitations of a stable isotope approach |
publisher |
AMER SOC LIMNOLOGY OCEANOGRAPHY |
publishDate |
2003 |
url |
http://nora.nerc.ac.uk/id/eprint/10200/ |
long_lat |
ENVELOPE(12.917,12.917,-69.967,-69.967) ENVELOPE(141.378,141.378,-66.787,-66.787) ENVELOPE(7.000,7.000,-68.000,-68.000) ENVELOPE(-68.000,-68.000,-68.500,-68.500) |
geographic |
Antarctic Southern Ocean Lazarev Marguerite Lazarev Sea Marguerite Bay |
geographic_facet |
Antarctic Southern Ocean Lazarev Marguerite Lazarev Sea Marguerite Bay |
genre |
Antarc* Antarctic Euphausia superba Lazarev Sea Mesozooplankton Southern Ocean Copepods |
genre_facet |
Antarc* Antarctic Euphausia superba Lazarev Sea Mesozooplankton Southern Ocean Copepods |
op_relation |
Schmidt, K.; Atkinson, A.; Stubing, D.; McClelland, J.W.; Montoya, J.P.; Voss, M. 2003 Trophic relationships among Southern Ocean copepods and krill: some uses and limitations of a stable isotope approach. Limnology and Oceanography, 48 (1). 277-289. |
_version_ |
1766214047882018816 |