UNVEILING PICOEUKARYOTIC DIVERSITY AND DISTRIBUTION IN THE BAY OF LARGE RESERVOIR SYSTEM

Few studies have reported about the diversity and distribution of picoeukaryotes in the ecosystem of reservoir bay. In this study, Sanger-based clone libraries of 18S rRNA gene were used to determine the picoeukaryotic diversity of three sampling sites; these sites were located across the Xiangxi Bay of Three Gorges Reservoir, China The sampling sites were monitored across all four seasons in 2013. We identified 13 phyla in Xiangxi Bay. In this experimental survey, we found that picoeukaryotic community was dominated by three main phyla, namely, Cryptophyta, Chlorophyta, and Ciliophora (69.9% of clones in all). Moreover, the remaining 10 phyla showed a relative abundance of less than 6%. In Xiangxi Bay, the seasonal variability of communities overwhelms spatial patterns; upper reaches exhibited highest species diversity, whereas middle reaches exhibited lowest species diversity. The community temporal stability had decreased from upstream to downstream. Primary producers were dominant in all the sample sites, irrespective of the season. In Xiangxi Bay upstream, terrestrial microbes may be integral components of the microbial community assembly. In Xiangxi Bay, the distribution pattern of picoeukaryotes might have been affected by the mainstream of Three Gorges Reservoir.