Inter-Research
Aquatic Microbial Ecology

ABSTRACT: The spatial distribution of ciliates in a Mediterranean interstitial community was analysed. During spring and summer ciliates tend to form patches and to stratify reaching their maximal density 3 to 6 cm below the surface. These patches are a few centimeters wide and deep and, in many cases, show the codominance of several taxa. Together with the distribution of ciliates, that of flagellates and culturable aerobic-heterotrophic bacteria was examined; these microorganisms too show wide variations in their distribution. A close, positive correlation was found between ciliate and flagellate abundance, together with a frequent overlap of their patches. These findings suggest that they interact or respond to the same environmental factors. The scarcity of bacterivorous ciliate species in the area could account for the lack of correlation between ciliates and aerobic-heterotrophic bacteria. Differences in the spatial distribution of interstitial oxygen content and porosity, over small distances, were also found. Some species seem to be sensitive to these factors, but an influence on overall ciliate abundance was not identified. Variations were found in ciliate taxonomic composition between neighbouring samples; they may be explained by local, undetermined, microenvironmental factors or by different recolonization phases in each sample.

KEY WORDS: Sandy shore . Distribution pattern . Interstitial environment . Ciliates . Mediterranean Sea

Published in AME Vol. 9, No. 1 (1995) on April 28
Print ISSN: 0948-3055; Online ISSN: 1616-1564. Copyright © Inter-Research, Oldendorf/Luhe, 1995