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Seasonal Zooplankton Concentrations in Barren River Lake and Tailwater, Kentucky

1982; Taylor & Francis; Volume: 1; Issue: 6 Linguagem: Inglês

10.1080/02705060.1982.9664086

2156-6941

Jerry F. Novotny, Robert D. Hoyt,

Water Quality and Pollution Assessment

ABSTRACT Microcrustacean plankton and rotifers were sampled semimonthly in Barren River Lake and at three stations in the tailwater from August 1980 to August 1981. Microcrustaceans were most abundant in the reservoir, and densities in the tailwater decreased progressively downstream. Three seasonal abundance peaks were observed in the reservoir—the highest in March-April and moderate ones in June and December. Fewest microcrustaceans were collected in late July and August in both the reservoir and tailwater. Rotifer densities were similar in the reservoir and in the immediate tailwater; however, densities usually declined progressively with distance below the dam. Densities were highest in January and February and decreased during the rest of the year; in some months no rotifers were collected. The decrease in abundances of microcrustaceans and rotifers downstream from the dam was attributed to predation, physical destruction, and lack of suitable habitat. Most water released from Barren River Lake was from the lower levels of the reservoir. During stratification (May—September), releases were from the hypolimnion, which normally harbors few living zooplankters. However, the higher abundance of zooplankton in the tailwater than in the hypolimnion suggested that water and associated organisms were also being withdrawn from higher levels in the reservoir. When the reservoir was unstratified, densities of zooplankton were usually lower in the tailwater than in the reservoir.