基于种群、功能群对比分析洞庭湖浮游植物群落驱动因素及水质评价

Phytoplankton is the most important component of water ecosystems, which could indicate the State of the water environment owing to its sensitivity to water environment Variation. However, its response to the environment is influenced by Classification methods. To understand the phytoplankton population(phyla and genera) and functional groups(FG) for driving response characteristics and applicability to the environment in Dongting Lake, a total of four samples were colleeted from the lake from Mareh to December 2019, and the Distribution eharacteristics of the phytoplankton population and functional groups and their responses to environmental factors were compared and analyzed. Meanwhile, the applicability of the TLI index, Shannon-Wiener index, and Q index was compared in Dongting Lake. The results showed that a total of 61 genera belonging to six phyla of phytoplankton were deteeted in Dongting Lake, which could be divided into 23 functional groups and nine dominant functional groups. The succession trend of functional groups was P/MP/D(March) —? MP/P/J(June) —HV1P/H1(September) —? Y/P/MP(December). The results of hierarchical segmentation showed that the population distribution and ehange in phytoplankton were driven by environmental factors more than the area in Dongting Lake. The main environmental factors affecting phytoplankton population and functional groups were water temperature(WT), permanganate index, dissolved oxygen(DO), conduetivity(Cond), water level(WL), and total phosphorus(TP). RDA analysis showed that phytoplankton functional groups identified phytoplankton response to environmental factors better than phytoplankton population. It was shown that using the Q index to evaluate water quality had better applicability in Dongting Lake.