Colonization dynamics of periphytic ciliates at different water depths in coastal waters of the Yellow Sea, northern China

Abstract

Abstract The colonization features of ciliate communities have proved to be a useful tool for indicating water quality status in aquatic ecosystems. To determine an optimal water depth for bioassessment using these ecological bioindicators, the colonization process of periphytic ciliates was studied at four depths of 1, 2, 3.5 and 5 m in Chinese coastal waters. Samples were collected at time intervals of 3, 7, 10, 14, 21 and 28 days using glass slides. The periphytic ciliate communities represented similar colonization dynamics from a depth of 1 to 3.5 m: (1) the temporal variability was well fitted to the MacArthur-Wilson and logistic models; (2) the species composition reached an equilibrium during the exposure time periods of 10–14 days; and (3) the maximum abundances were definitely higher at a depth of 1 m than those at 3.5 m. PERMANOVA test revealed that the colonization pattern at 1 m depth was significantly different from those at the other three depths. Results suggest that the colonization dynamics of periphytic ciliates may be influenced by water depth in coastal waters. These findings provide an important reference for establishing an optimal sampling strategy for bioassessment on large spatial/temporal scales in marine ecosystems.