000K  utf8
1100  $c2007
1500  eng
2050  urn:nbn:de:gbv:8-diss-19224
3000  Knotz, Susanna
4000  Trophic interactions in the pelagic$hChristian-Albrechts-Universität zu Kiel  [Knotz, Susanna]
4030  Kiel$nChristian-Albrechts-Universität zu Kiel
4209  Physiological and nutritional factors that influence the population dynamics of North Sea copepods were identified. Five digestive enzymes were measured in individual copepods. Short-term starvation elicited complex enzyme reactions. Protease isozyme patterns did not change. Seston C:N and POP:TPP correlated with reproductive success. Grazing behaviour and digestive system mediated the effect. Copepods took up N:P in ratios matching their body ratios. C:N and POP ingestion followed the seston pattern. Compensatory feeding was observed. Food quality and stable isotope signatures changed over time (Helgoland, 2004-2005) and between GLOBEC-stations (southern North Sea). Seston d15N and d13C revealed major composition shifts in spring and a strong heterotroph component in summer. A. clausi and T. longicornis utilised different carbon sources despite similar high trophic levels. A low seston d13C (spring) was favourable. Chitobiase activity indicated C assimilation, the other enzymes N assimilation. A low body d13C may denote high turnover rates. Combining methods explains zooplankton- phytoplankton interactions better than only one approach.
4950  https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-19224$xR$3Volltext$534
4961  https://macau.uni-kiel.de/receive/diss_mods_00001922
5051  550
5550  C:N:P
5550  digestive enzymes
5550  elemental uptake
5550  Ernährung
5550  GLOBEC
5550  grazing behaviour
5550  Helgoland
5550  Nordsee
5550  North Sea copepods
5550  protease isozymes
5550  Ruderfußkrebse
5550  seston quality
5550  stable isotope ratios