Spatial distribution characteristics and driving factors of benthic ciliates in northern China

In October 2020, we sampled the benthic ciliate communities in 14 sandy intertidal zones in northern China to gain insight into the relative influence of diverse geographical scale parameters on driving the spatial pattern of microbial communities. The main findings were as follow: (1) 105 ciliates were identified belonging to 65 genera and 26 orders, and Pleuronematida, Microthoracida, and Cyclotrichida were the dominant groups; (2) although significant differences in environmental conditions were detected between the Yellow Sea and the Bohai Sea, the community composition of ciliates did not show significant difference; (3) partial Mental test revealed that environmental factors were more important than spatial distance in determining ciliate community composition, with salinity, grain size, and beach slope were the most important environmental factors in explaining ciliate spatial distribution, while tidal range and dissolved inorganic nitrogen content were less important; (4) in coastal areas, the mass effect of microorganisms somewhat hided the effects of environmental heterogeneity. In conclusion, because microorganisms in coastal environments were less restricted by dispersal, environmental variables played a larger role in the establishment of spatial distribution patterns than spatial distance. This research gives basic information on marine microbial biogeography, which can aid beach management and conservation planning in the face of global change.