Trophic structure and energy flow in backwater lakes of two large floodplain rivers assessed using stable isotopes

Brian R. Herwig, Daniel A. Soluk, John M. Dettmers, David H Wahl

Research output: Contribution to journalArticle

Abstract

Carbon and nitrogen stable isotopes (δ13C and δ15N, respectively) were measured for locally abundant primary producers, detritus, aquatic invertebrates, and fish in backwater lakes of two large floodplain rivers in an effort to understand patterns of energy dependence and trophic structure within these habitats. We observed trophic enrichment values for 15N that were within the ranges observed for other aquatic systems but were often considerably lower than the 3.4‰ typically assumed in stable isotope studies. Production based on benthic and terrestrial material, combined with planktonic production for larval fish, appears to be an important energy source supporting consumers in backwater lakes of large floodplain rivers. Our isotopic data challenge the conventional wisdom that macrophytes are centrally involved in supplying carbon to aquatic consumers in shallow lakes and that food webs in most lakes are sustained almost exclusively by carbon fixed by phytoplankton.

Original languageEnglish (US)
Pages (from-to)12-22
Number of pages11
JournalCanadian Journal of Fisheries and Aquatic Sciences
Volume61
Issue number1
DOIs
StatePublished - Jan 1 2004

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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