Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level
We hypothesized that the trophic level of marine copepods should depend on the composition of the protist community. To test this hypothesis, we manipulated the phytoplankton composition in mesocosms and measured grazing rates of copepods and mesozooplankton in those mesocosms. Twelve mesocosms with...
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ftoceanrep:oai:oceanrep.geomar.de:504 2023-05-15T17:41:31+02:00 Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level Sommer, Ulrich Hansen, Thomas Blum, Olga Holzner, Nina Vadstein, Olav Stibor, Herwig 2005 text https://oceanrep.geomar.de/id/eprint/504/ https://oceanrep.geomar.de/id/eprint/504/1/Sommer%20et.al.pdf https://doi.org/10.1007/s00442-004-1708-y en eng Springer https://oceanrep.geomar.de/id/eprint/504/1/Sommer%20et.al.pdf Sommer, U., Hansen, T., Blum, O., Holzner, N., Vadstein, O. and Stibor, H. (2005) Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level. Oecologia, 142 . pp. 274-283. DOI 10.1007/s00442-004-1708-y <https://doi.org/10.1007/s00442-004-1708-y>. doi:10.1007/s00442-004-1708-y info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2005 ftoceanrep https://doi.org/10.1007/s00442-004-1708-y 2023-04-07T14:42:04Z We hypothesized that the trophic level of marine copepods should depend on the composition of the protist community. To test this hypothesis, we manipulated the phytoplankton composition in mesocosms and measured grazing rates of copepods and mesozooplankton in those mesocosms. Twelve mesocosms with Northeast Atlantic phytoplankton were fertilised with different Si:N ratios from 0:1 to 1:1. After 1 week, ten of the mesocosms were filled with natural densities of mesozooplankton, mainly calanoid copepods, while two remained as mesozooplankton-free controls. Both before and after the addition of copepods there was a positive correlation of diatom dominance with Si:N ratios. During the second phase of the experiment, copepod and microzooplankton grazing rates on different phytoplankton species were assessed by a modification of the Landry-Hassett dilution technique, where the bottles containing the different dilution treatments were replaced by dialysis bags incubated in situ. The results indicated no overlap in the food spectrum of microzooplankton (mainly ciliates) and copepods. Ciliates fed on nanoplankton, while copepods fed on large or chain-forming diatoms, naked dinoflagellates, and ciliates. The calculated trophic level of copepods showed a significantly negative but weak correlation with Si:N ratios. The strength of this response was strongly dependent on the trophic levels assumed for ciliates and mixotrophic dinoflagellates. Article in Journal/Newspaper Northeast Atlantic Copepods OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Oecologia 142 2 274 283 |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
We hypothesized that the trophic level of marine copepods should depend on the composition of the protist community. To test this hypothesis, we manipulated the phytoplankton composition in mesocosms and measured grazing rates of copepods and mesozooplankton in those mesocosms. Twelve mesocosms with Northeast Atlantic phytoplankton were fertilised with different Si:N ratios from 0:1 to 1:1. After 1 week, ten of the mesocosms were filled with natural densities of mesozooplankton, mainly calanoid copepods, while two remained as mesozooplankton-free controls. Both before and after the addition of copepods there was a positive correlation of diatom dominance with Si:N ratios. During the second phase of the experiment, copepod and microzooplankton grazing rates on different phytoplankton species were assessed by a modification of the Landry-Hassett dilution technique, where the bottles containing the different dilution treatments were replaced by dialysis bags incubated in situ. The results indicated no overlap in the food spectrum of microzooplankton (mainly ciliates) and copepods. Ciliates fed on nanoplankton, while copepods fed on large or chain-forming diatoms, naked dinoflagellates, and ciliates. The calculated trophic level of copepods showed a significantly negative but weak correlation with Si:N ratios. The strength of this response was strongly dependent on the trophic levels assumed for ciliates and mixotrophic dinoflagellates. |
format |
Article in Journal/Newspaper |
author |
Sommer, Ulrich Hansen, Thomas Blum, Olga Holzner, Nina Vadstein, Olav Stibor, Herwig |
spellingShingle |
Sommer, Ulrich Hansen, Thomas Blum, Olga Holzner, Nina Vadstein, Olav Stibor, Herwig Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level |
author_facet |
Sommer, Ulrich Hansen, Thomas Blum, Olga Holzner, Nina Vadstein, Olav Stibor, Herwig |
author_sort |
Sommer, Ulrich |
title |
Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level |
title_short |
Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level |
title_full |
Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level |
title_fullStr |
Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level |
title_full_unstemmed |
Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level |
title_sort |
copepod and microzooplankton grazing in mesocosms fertilised with different si:n ratios: no overlap between food spectra and si:n influence on zooplankton trophic level |
publisher |
Springer |
publishDate |
2005 |
url |
https://oceanrep.geomar.de/id/eprint/504/ https://oceanrep.geomar.de/id/eprint/504/1/Sommer%20et.al.pdf https://doi.org/10.1007/s00442-004-1708-y |
genre |
Northeast Atlantic Copepods |
genre_facet |
Northeast Atlantic Copepods |
op_relation |
https://oceanrep.geomar.de/id/eprint/504/1/Sommer%20et.al.pdf Sommer, U., Hansen, T., Blum, O., Holzner, N., Vadstein, O. and Stibor, H. (2005) Copepod and microzooplankton grazing in mesocosms fertilised with different Si:N ratios: no overlap between food spectra and Si:N influence on zooplankton trophic level. Oecologia, 142 . pp. 274-283. DOI 10.1007/s00442-004-1708-y <https://doi.org/10.1007/s00442-004-1708-y>. doi:10.1007/s00442-004-1708-y |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1007/s00442-004-1708-y |
container_title |
Oecologia |
container_volume |
142 |
container_issue |
2 |
container_start_page |
274 |
op_container_end_page |
283 |
_version_ |
1766143107564306432 |