Eukaryotic phytoplankton community composition in Tibetan glacial lakes analyzed by high throughput sequencing

Phytoplankton is important for the primary productivity of natural waters．In the context of global climate changes, glacial lakes in high altitude regions are increasing and expanding, community structure of phytoplankton in such glacial lakes undergo rapid changes．High throughput sequencing offers simplicity, rapidity and low error rates, therefore could be used to investigate and analyze distribution and changes of phytoplankton in glacial lakes．The surface and bottom water from three different glacial lakes in the Kuoqionggangri Glacier Basin, Tibet, were sequenced and analyzed in this study．The variable region in 18S rRNA gene V4 was used to study diversity of eukaryotic phytoplankton in glacial lakes．Number of bases used for annotation accounted for > 97%, so measurements were accurate and reliable．Chlorophyta and Cryptophyta were found to be dominant in the glacial Lakes．The absolutely dominant species were found to be Chlamydomonadaceae_sp. (0.127) and Chlorophyta (0.112)．The water body in Kuoqionggangri Glacial Lake was alkaline; with high turbidity and wide range, low water temperature, low levels of nutrients and chlorophyll a, the lake is in poor nutrition status．Dominant species and communities of phytoplankton at different sampling points in the same glacial lake, and in different glacial lakes varied markedly, possibly due to differences in glacial meltwater recharge and solar radiation．Dominant species and communities of phytoplankton in glacial lakes were quite different from large lakes on the Tibetan Plateau, but similar to small alpine lakes abroad．Therefore overall distribution and changes in dominant species of phytoplankton were more consistent in small lakes in alpine mountains．This study furthers investigation and understanding of phytoplankton community in high-altitude glacial lakes．