Aquatic Sciences Meeting, Albuquerque 2001

CS40 Nutrients, Primary Production, and Aquatic Ecosystems

Date: Wednesday, February 14, 2001, Time: 2:00:00 PM

Location: La Cienega

Chan, F, , Cornell University, Institute of Ecosystem Studies, Ithaca, USA, fc19@cornell.edu

Pace, M, L, Institute of Ecosystem Studies, Millbrook, USA, pacem@ecostudies.org

Howarth, R, W, Oceans Program, Environmental Defense, Boston, USA, bhowarth@environmentaldefense.org

The turnover of pelagic autotrophic biomass: comparative analyses of freshwater and coastal marine ecosystem processes

Primary production and its subsequent loss by consumption and physical export regulate the turnover rate of phytoplankton biomass. Variations in turnover rates have important implications for the functional composition of pelagic communities, the trophic structuring of biomass and the limits to nutrient cycling and primary production. The extent to which turnover rates remain constant or vary systematically across broad ranges of aquatic ecosystems is unclear. We have synthesized a large database on reported turnover rates of pelagic autotrophic biomass across broad gradients of productivity and nutrient availability in freshwater (n=401) and coastal marine systems (n=121). Across systems, turnover rates showed no systematic tendency to increase or decrease along gradients of productivity and nutrient availability. In addition, our results indicate that turnover rates in coastal marine systems are nearly 3-fold higher than those in freshwater systems. The cross-system patterns of turnover rates reported here point to fundamental differences in the structure and fates of primary production between marine and freshwater planktonic systems.

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Aquatic Sciences Meeting, Albuquerque 2001

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