Grazers as Sources and Sinks for Nutrients: Conclusions, Limitations, and Speculations
The trophic-dynamic school in ecology, pioneered by Lindeman (1942), has typically used mass or energy equivalents for the quantitative description of interactions between trophic levels. Progress in the direction envisioned by Vollenweider (1976), of coupling input-output models with a trophicdynamic view of ecosystems, would require also the consideration of flows of limiting nutrients among trophic levels. The flow networks of energy and essential elements cannot be simple mirror images of each other, since, for example, energy flows unidirectionally from autotrophs to herbivores, while nutrients flow bidirectionally between the same two trophic levels. As pointed out by Reiners (1986), the energetic and stoichiometric views of ecosystem organization, as expressed by e.g., Odum (1957) and Redfield (1958), must therefore be seen as complementary and irreducible parts of models describing trophic relationships in nutrient-limited ecosystems.
KeywordsDilution Rate Algal Biomass Zooplankton Biomass Daphnia Population Nutrient Supply Rate
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