CS35 Trophic Dynamics
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
ChumchalMM, Texas Christian University, Ft. Worth, USA, chumchalm@yahoo.com
Drenner, R, W, Texas Christian University, Ft. Worth, USA, r.drenner@tcu.edu
 
INTERRELATIONSHIPS BETWEEN NUTRIENTS, FISH, AND SUPPLEMENTAL FEEDING IN THE REGULATION OF PHYTOPLANKTON BIOMASS
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We performed a 4-week summer mesocosm experiment of factorial design that consisted of 2 levels of phosphorus loading (with/without) cross-classified with 2 levels of benthivorous fish (with/without common carp) and 2 levels of supplemental feeding (with/without commercial fish pellets). The 2 x 2 x 2 design resulted in 8 treatment combinations, each with triplicate replication. Mesocosms were sampled weekly for TN, TP, phytoplankton biomass, and turbidity. We detected main effects of nutrients, fish, and supplemental feeding on phytoplankton biomass. We detected all possible 2-way interaction effects and a 3-way interaction effect indicating that nutrient loading, fish, and supplemental feeding did not operate independently to regulate phytoplankton biomass. Nutrient loading and fish interacted synergistically to enhance phytoplankton biomass but supplementary feeding dampened the magnitude of the synergism.