The zooplankton community of Lake Dillon is exceedingly simple in composition. More than 99% of the individuals in the community are accounted for by four species, including three species of rotifer and one species of copepod. The rotifers are Polyarthra vulgaris Carlin, Keratella cochlearis (Gosse), and Keratella quadrata (Müller). Each of these three species is found in a wide variety of lake types. Only the first two of these three rotifer species are really important, since Keratella quadrata does not reach abundances of more than 10% of either the other two species of rotifer. The Copepoda are represented by a single species (Diacyclops bicuspidatus thomasi Forbes). This is generally regarded as a cold-water species; at low elevations there are few reports of summer populations (Armitage and Tash 1967). Cladocerans (mainly Bosmina) appeared only in very small numbers during the study period.
KeywordsBiomass Chlorophyll Depression Phytoplankton Stratification
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