Contribution
Isotopic variation complicates analysis of trophic relations within the fish community of Plußsee: a small, deep, stratifying lake
Harrod, Chris; Grey, Jonathan
Archiv für Hydrobiologie Volume 167 Number 1-4 (2006), p. 281 - 299
64 références bibliographiques
publié: Oct 5, 2006
DOI: 10.1127/0003-9136/2006/0167-0281
ArtNo. ESP141016770018, Prix: 29.00 €
Abstract
Analysis of carbon and nitrogen stable isotopes has allowed freshwater ecologists to examine lake food webs in increasing detail. Many such studies have highlighted the existence of separate within-lake pelagic and benthic-littoral food webs but are typically conducted on large (>10km2) lakes, whereas the majority of lakes are actually relatively small. We used stable isotope analysis (δ13 C & δ15 N) to examine trophic interactions between fish and their prey in Plußsee, as an example of a small, stratifying lake, and to determine whether separate pelagic/benthic-littoral food webs could be distinguished in such systems. Our results indicate that the Plußsee food web was complicated, and due to extensive intra-annual isotopic variation in zooplankton (e. g. cladoceran δ13 C annual range = 25. 6 ‰), it may be impossible to definitively assign consumers from small, eutrophic stratified lakes to pelagic or benthic-littoral food webs. We present evidence that some components of the Plußsee food web (large bream) may be subsidised by carbon of methanogenic origin.
Mots-clefs
δ13 C • δ15 N • stable isotope analysis • food web • lake size • pelagic • benthic littoral