Effects of zooplankton on sedimentation in pelagic ecosystems: Theory and test in two lakes of the Canadian shield

James Elser, Dean K. Foster, Robert E. Hecky

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

A simple heuristic theory based on conservation of matter and describing the fate of autotrophic production in pelagic ecosystems was developed to assist in conceptualizing how zooplankton affect sedimentation processes in lakes and oceans. The theory predicted that effects of zooplankton on the fraction of autotrophic incorporation that sediments (the "export ratio") will be a function of factors related both to zooplankton digestion and egestion and to tendencies of particulate matter to sediment directly prior to mineralization. As a result, effects of zooplankton grazing on the export ratio were predicted to be site-dependent, a function of physical conditions and zooplankton communities characterizing an ecosystem. The theory was tested by monitoring autotrophic production of C, N, and P, sedimentation of C, N, and P, and zooplankton biomass in two lakes of the Canadian shield characterized by contrasting morphometry and food-web structure. In Lake 110, a small elongate lake protected from wind exposure, export ratios of C, N, and P declined strongly with zooplankton biomass. In contrast, in L240, a larger lake with considerably greater wind exposure, export ratios increased with zooplankton biomass. These results were consistent with predictions of our theory that effects of zooplankton on sedimentation processes will depend on the tendency of particulate matter to directly sediment relative to the tendency of egested materials to sediment. However, no significant differences in relationships between export ratios for C, N, and P and zooplankton biomass were found.

Original languageEnglish (US)
Pages (from-to)143-170
Number of pages28
JournalBiogeochemistry
Volume30
Issue number3
DOIs
StatePublished - Sep 1 1995

Keywords

  • export ratio
  • grazing
  • nutrients
  • sedimentation
  • zooplankton

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Earth-Surface Processes

Fingerprint Dive into the research topics of 'Effects of zooplankton on sedimentation in pelagic ecosystems: Theory and test in two lakes of the Canadian shield'. Together they form a unique fingerprint.

  • Cite this