Aquatic Sciences Meeting, Albuquerque 2001

PC12 Trophic Dynamic Studies

Date: Thursday, February 15, 2001

Location: Southwest Hall

Sawyer, R, , Oceanography, University of Washington, Box 357940, Seattle, WA 98105, USA, sawyerrc@u.washington.edu

Sackmann, B, , Oceanography, University of Washington, Box 357940, Seattle, WA 98105, USA, bssackma@u.washington.edu

VARIABILITY IN CALANUS PACIFICUS REPRODUCTIVE FITNESS IN RESPONSE TO CHANGES IN PHYTOPLANKTON FOOD QUALITY.

Mesozooplankton secondary production in aquatic food webs is critical in the energy transfer of primary producers to higher trophic levels. A variety of properties determine the quality of phytoplanton as a food source and influence the efficiency of energetic transfer to zooplankton. Copepod reproductive fitness and its relation to changes in food quality was investigated along a six station transect extending from the main basin of Puget Sound, Washington into Hood Canal, Washington during 3-7 April 2000. Several parameters indicative of phytoplankton quality as a food source, including total protein content, organic carbon to nitrogen ratios, and chlorophyll a to phaeopigment ratios, were measured. Copepod reproductive fitness was determined by measuring prosome lengths, egg diameters, and egg production rates of Calanus pacificus. Positive correlations between the selected food quality parameters and copepod reproductive fitness suggest that their use is a valid approach for predicting and quantifying secondary production.

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Aquatic Sciences Meeting, Albuquerque 2001

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