Impacts of anthropogenic activities on eukaryotic phytoplankton communities in Panlong River via eDNA biomonitoring.

As environmental indicators, phytoplankton community variations often indicated the effects of anthropogenic activities on aquatic ecosystem. Efficient and accurate monitoring of phytoplankton is of great significance for water ecological assessment and conservation. We aimed to explore the impacts of anthropogenic activities on an urban river ecosystem via environmental DNA metabarcoding biomonitoring of eukaryotic phytoplankton communities at Panlong River in Kunming, Yunnan, China. 257 Species/genera eukaryotic phytoplankton were detected, and distinct spatial and seasonal variations of phytoplankton community (e.g., ASVs number, dominant taxon, the relative abundances) were observed in Panlong River. The species number (170 species/genera in dry period and 236 species/genera in wet period) and the abundances of Cryptophyta increased from dry period to wet period, while the relative abundances of Bacillariophyta and Dinophyta decreased. The diversities were higher in wet period than in dry period, and there were also significant differences among upstream, midstream and downstream. Redundancy analysis showed the water temperature was the key environmental stressor affecting phytoplankton community structures both in dry and wet periods, while the influences of other environmental factors varied in different periods and different sites. This study provides insights on phytoplankton diversity monitoring and the management of urban rivers. [ABSTRACT FROM AUTHOR]