Benthic–planktonic coupling, regime shifts, and whole-lake primary production in shallow lakes

Autor: Erik Jeppesen, Motomi Genkai-Kato, Yvonne Vadeboncoeur, Lone Liboriussen
Rok vydání: 2012
Předmět:
Zdroj: Genkai-Kato, M, Vadeboncouer, Y, Liboriussen, L & Jeppesen, E 2012, ' Benthic–planktonic coupling, regime shifts, and whole-lake primary production in shallow lakes ', Ecology, vol. 93, pp. 619-631 .
ISSN: 0012-9658
DOI: 10.1890/10-2126.1
Popis: Alternative stable states in shallow lakes are typically characterized by submerged macrophyte (clear-water state) or phytoplankton (turbid state) dominance. However, a clear-water state may occur in eutrophic lakes even when macrophytes are absent. To test whether sediment algae could cause a regime shift in the absence of macrophytes, we developed a model of benthic (periphyton) and planktonic (phytoplankton) primary production using parameters derived from a shallow macrophyte-free lake that shifted from a turbid to a clear-water state following fish removal (biomanipulation). The model includes a negative feedback effect of periphyton on phosphorus (P) release from sediments. This in turn induces a positive feedback between phytoplankton production and P release. Scenarios incorporating a gradient of external P loading rates revealed that (1) periphyton and phytoplankton both contributed substantially to whole-lake production over a broad range of external P loading in a clear-water state; (2) during the clear-water state, the loss of benthic production was gradually replaced by phytoplankton production, leaving whole-lake production largely unchanged; (3) the responses of lakes to biomanipulation and increased external P loading were both dependent on lake morphometry; and (4) the capacity of periphyton to buffer the effects of increased external P loading and maintain a clear-water state was highly sensitive to relationships between light availability at the sediment surface and the of P release. Our model suggests a mechanism for the persistence of alternative states in shallow macrophyte-free lakes and demonstrates that regime shifts may trigger profound changes in ecosystem structure and function.
Databáze: OpenAIRE
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