Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.592382
Title: The effects of temperature fluctuations on communities of ciliate protozoa : an experimental study
Author: Eddison, J. C.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1981
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Abstract:
Six experiments were conducted to investigate the effect of environmental variations on the structure of ecological communities. Natural assemblages of freshwater ciliate protozoa were maintained in batch cultures and subjected to various regimes of temperature fluctuations. The cultures were sampled regularly throughout each experiment. The ciliates present in each sample were identified and counted. Estimates of the diversity of the ciliate assemblages were calculated from the results of the sampling, and it was through this property that the responses of the ciliate communities to temperature fluctuations were gauged. Results showed that ciliate diversity was significantly greater in those communities subjected to temperature fluctuations than those maintained at constant temperatures. Also, the diversity of the communities was related to the frequency of the temperature fluctuations to which they were subjected, high diversity being associated with the highest frequency of fluctuation. The diversity of the communities subjected to very slow frequencies of fluctuations did not differ from that of communities maintained at a constant temperature. Further analyses investigated the responses of the populations comprising the ciliate communities. These analyses showed no difference between treatments with respect to: the mean size of the ciliate populations, the degree to which the populations varied in size, and the frequency with which the populations varied in size. Also, the populations subjected to the two main temperature regimes did not differ from each other with respect to the amount of density-dependent regulation exhibited: there was little evidence of such regulation in any system. The results of all these analyses are discussed in relation to current theories of diversity maintenance. An alternative explanation is offered to account for the results; its relevance to ecological systems other than the microcosms used in this study is discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.592382  DOI: Not available
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