SEDL / STP / STP865-EB / STP35256S

Experimental Ponds for Evaluating Bioassay Predictions

deNoyelles, F
Professor, Department of Systematics and Ecology, and superintendent, Experimental and Applied Ecology Program, University of Kansas, Lawrence, KS

Kettle, WD
Professor, Department of Systematics and Ecology, and superintendent, Experimental and Applied Ecology Program, University of Kansas, Lawrence, KS

Pages: 13    Published: Jan 1985

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Abstract

Experimental pond studies were used to demonstrate a means of assessing the accuracy of laboratory and in situ bioassays predicting the effects of chemical stress on phytoplankton. A short-term batch bioassay using changing carbon uptake in photosynthesis predicted an immediate (first 24 h) effect of the herbicide atrazine on the phytoplankton communities in experimental ponds. After addition of atrazine to the ponds, the same decreases in carbon uptake were observed, but the appearance of resistant species that soon occurred could not be predicted with the short-term exposure used in such a bioassay. From another experimental pond study a longer-term continuous flow bioassay using changing species composition predicted an effect of increased nutrient and altered pH conditions over a 20-day exposure. With these same perturbations applied to experimental ponds, the same series of responses were observed. Comparison of responses in the experimental ponds with those in the bioassays was also used to demonstrate the general limits of applicability for each bioassay.