Abstract
Change over a week period in the population composition of marine ciliates attached to solid substrata was studied. A number of 0.1mm thick Teflon and about 1mm thick microscopic glass slides were placed at depth of 0.5m in seawater at Aburatsubo Inlet, Kanagawa-ken. Heterotrophic nanoplankton (HNP), ciliated protozoa, algae and DAPI-stained bacterial cells were counted using Nomarsky and fluorescent microscope. A video camera attached to the microscope was used for identification of ciliates. The numbers of bacteria, HNP, and algal population on the substrata were much higher than those in the surrounding water. Ciliates (1200 and 2400 cells/cm2 on glass and Teflon slides, respectively) appeared on the first day and seemed to feed actively on attached microorganisms. Among the dominant ciliate population (Dysteria, Aspidisca, Geleia, Litonotus, Euplotes, Holosticha and Loxophyllum), bacteriovorous ciliates attached within the first 3 days to both substrata followed by the appearance of herbivorous species. Twenty three and seventeen species of ciliates were found on Teflon and glass slides, respectively. The maximum diversity index was observed on the fourth day on both substrata. Succession of ciliate species should be due to the change in food composition despite the nature of the substrata.
