Succession of phytoplankton functional groups and driving variables in a young canyon reservoir

Abstract

Reservoir eutrophication is a global problem that needs to be urgently solved, and exploring phytoplankton dynamics in young reservoirs is extremely important for artificial intervention during the process of eutrophication. However, the succession of phytoplankton communities and their responses to environmental variables in young canyon reservoirs remain obscure. Therefore, phytoplankton functional group data were collected from a young canyon reservoir for 2 years, and the succession pattern and its response to environmental variables were simultaneously evaluated. The results revealed significant spatial differences and rapid interannual changes in some environmental variables (water temperature, suspended solids) in the young canyon reservoir. Non-metric multidimensional scaling showed that phytoplankton functional group structure differed obviously among the zones of the reservoir, while significant interannual succession (from the Lo and Y groups to the X2 group) occurred in the lacustrine zone. Additionally, redundancy analysis demonstrated that the structure of phytoplankton functional groups varied significantly between the spatially different environments. Finally, the succession of phytoplankton functional groups in the lacustrine zone was mainly driven by increases in nutrients and water temperature. The rules underlying and dominant mechanism driving short-term succession in the young canyon reservoir revealed in this study may provide a deeper understanding of the intervention mechanisms that could be implemented to alleviate reservoir eutrophication.