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The use of outdoor freshwater pond microcosms. III. Responses of phytoplankton and periphyton to pyridaben

R. M. Ross·W. F. Krise·Lori A. Redell·R. M. Bennett
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Abstract

An outdoor freshwater microcosm study was conducted in which pyridaben, an insecticide-miticide, was directly applied to water to determine its biological effects on phytoplankton and periphyton. Twenty-four microcosms (24 m3 each) were monitored for 11 months, then four treatments of pyridaben were applied two times at three concentrations (0.34, 34.0 ??g/L), including an untreated control. The succession of algal groups observed and the major genera found in microcosms during the baseline phase of the study were typical of oligo-mesotrophic systems in Florida. Following application of pyridaben, the most remarkable effect was a positive correlation of phytoplankton abundance with pyridaben concentrations in water; indicating increased abundance as a result of exposure. Both Chlorophyta and Pyrrophyta exhibited a significant increase (p=0.05) in population abundance at 3.4 and 34.0 ??g/L pyridaben. Chrysophyta also elicited a trend of increased abundance at 34.0 ??g/L, although the effect was not significant. The effects on phytoplankton populations were associated with the decline of zooplankton populations as a result of a direct effect of pyridaben exposure. There were no effects of pyridaben on periphyton communities or on functional endpoints. ?? 2001 by John Wiley & Sons, Inc.

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R. M. Ross, W. F. Krise, Lori A. Redell, R. M. Bennett. 2001. The use of outdoor freshwater pond microcosms. III. Responses of phytoplankton and periphyton to pyridaben. https://doi.org/10.1002/1522-7278(2001)16%3A1%3C96%3A%3Aaid-tox110%3E3.0.co%3B2-u

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