Effects of artificial destratification on zooplankton of two Oklahoma reservoirs

Abstract

Species composition and diversity of zooplankton were observed in two lakes undergoing destratification attempts. Twenty-five and twenty-four taxa were collected from Ham's and Arbuckle Lake, respectively. Species composition and density were similar to other area reservoirs, while diversity values (d) were consistently lower. No correlation was observed between depth and number of species or depth and diversity. Density tended to decrease with depth. Densities were lowest in April and August in Ham's Lake and in August in Arbuckles Lake. In both lakes, density was highest in May. Ham's Lake was artificially destratified by the pumping, while Arbuckle Lake was not destratified during the study. Although some temporal variation in species numbers and densities possibly reflected limited oxygen concentrations, the changes could not be directly related to physicochemical conditions of the lakes. Variations are probably due in part to seasonal population dynamics of the zooplankton. No correlation was observed between diversity and time.