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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 4700

James R. Pratt, Bruce Z. Lang, Roger L. Kaesler, and John Cairns, Jr.; Effect of Seasonal Changes on Protozoans Inhabiting Artificial Substrates in a Small Pond. Arch.Protistenk 131:45-57, 1986

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Effects of seasonal variation on the structure of protozoan communities were investigated by comparing interactive, equilibrium communities that had colonized polyurethane foam artificial substrates. Substrates were colonized near the surface and bottom of a 1 m deep, eutrophic pond and sampled at weekly or bi-weekly intervals over an annual cycle. No seasonal differences were apparent. Numbers of species were relatively constant except during periods of heavy rainfall or ice melt. Species numbers were significantly, negatively correlated with dilution of the water column. Similarity between samples decreased with increasing time between samples; however, samples taken as much as 30 weeks apart retained a small, residual similarity. Residual similarity was interpreted to be a core community of species. Cluster analysis revealed a generally orderly transition in species composition over time. Stable species numbers in these communities and the rapid change and recovery of species numbers during perturbations make these communities especially valuable in assessing acute impacts on freshwater ecosystems.