An Ecological Study of Brackish Water Ciliates

Abstract

Sixty-one spp. recorded of Ciliophora occurring in brackish water at Parkgate, Cheshire. Distribution of commonest spp. cannot be related directly to seasonal or tidal change or to gross fluctuations in temperature, salinity or hydrogen-ion concentration. Ciliates recorded classified according to whether they occur in interstitial spaces of mud or associated with diatom films. Many spp. in latter group may be found occasionally in intergranular spaces, but achieve greatest numbers in association with films. A few spp. occur exclusively in interstitial spaces, and a few spp. are always found attached to diatom films. Latter are all diatom feeders and may attain large numbers of single sp. at any one time. Ciliates associated with diatom films occur in communities having a distinct social structure, which is descr. Occurrence of communities depends upon (1) presence of abundant microflora, consisting of bacteria and diatoms, as source of food; (2) presence of film of organic matter, produced mainly by secretory activities of microflora. Suggested that composition of ciliate fauna may be influenced by biochemical suitability of available microflora as food, together with its suitability of size and shape in relation to feeding mechanisms of ciliates concerned.