Protist diversity in a marine and lacustrine system: Patterns across a salinity gradient

Summary

During the last decade, the improvement of high-throughput sequencing (HTS) techniques has substantially increased our insight into microbial ecology, by capturing a much more detailed picture of their diversity. Due to the increasing amount of data obtained by HTS methods, specific questions on the biogeography and factors explaining the distribution of these microorganisms can now be fully examined. Here, the composition and structure of a metabolically active benthic protistan community was investigated along a salinity gradient of closely associated marine and freshwater systems. Amplicons of rDNA and rRNA, were sequenced using the Illumina MiSeq technology. This approach seemed to successfully capture the majority of the protist community in these habitats. The marine environments displayed a higher species richness compared to the lacustrine systems investigated, and a considerable difference in protist composition was observed between marine and freshwater systems. Nevertheless, some protists were found in both saline and freshwater environments, indicating the ability to survive rather diverse environmental conditions. It is noteworthy that some of the OTUs from both habitats form putative new clades in the enigmatic X-cell group.