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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 994

Douglas E. Gill; Density dependence and population regulation in laboratory cultures of Paramecium. Ecology 53(4):701-708, 1972

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Two experiments with laboratory cultures of Paramecium were performed on test the hypotheses that (1) density is limited by food, and (2) dissolved oxygen in culture tubes of narrow shape is the primary limiting resource. The procedure for estimating saturation density was not repeatable over years and probably abnormally inflated the estimate of sampling error in the experiments. Differences observed between treatments were therefore of dubious biological significance. On the other hand, the estimates of intrinsic growth rates were reliable and repeatable. Contrary to expectation, all the species grew slower in food-enriched medium than in unenriched medium, and no effect of oxygen limitation could be demonstrated. It is concluded that population density regulation of Paramecium is principally determined by accumulation of metabolic wastes of bacteria and the ciliates themselves.