Spatial and seasonal variations of large tintinnid ciliates in Shenhu Bay of China

In this study, the spatial distribution and seasonal variation of large tintinnids (>76 μm) were investigated in Shenhu Bay during three seasons of 2012. Of the 36 species identified, 9 were dominant (i.e. Tintinnopsis radix, Leprotintinnus simplex, Tintinnopsis japonica, Tintinnopsis tubulosoides, Leprotintinnus nordqvisti, Tintinnopsis beroidea, Stenosemella parvicollis, Tintinnidium primitivum, Tintinnopsis nana). A clear seasonal shift of the taxonomic composition as well as the lorica size of the dominant species was observed. The highest numbers of tintinnid species occurred in spring, while the highest abundance and biomass occurred in summer. Clustering indicated that the seasonal variations of the community structure were more obvious than spatial variations. Spearman correlation analysis revealed that density of phytoplankton prey had a significant impact on the tintinnid abundance. Redundancy analysis (RDA) illustrated that temperature, salinity and the nutrient level were the most important abiotic factors affecting the spatial and seasonal pattern of tintinnid communities in Shenhu Bay.