Abstract: To understand the temporal and spatial distribution of phytoplankton functional groups in Daqing Longfeng wetland, we collected the samples in the spring, summer, and autumn of 2019. A total of 200 taxa of phytoplankton were identified, belonging to 7 phyla, 10 classes, 18 orders, 35 families, and 75 genera. Among them, Chlorophyta (41.5%) and Bacillariophyta (30%) were the dominant groups, followed by Cyanophyta (12.5%) and Euglena (12%), while the abundance of Cryptophyta, Dinophyta, and Chrysophyta were relatively low (together accounting for 4%). The composition of phytoplankton in the Longfeng wetland changed obviously among different seasons, with the abundance of phytoplankton following a seasonal trend of summer < spring < autumn. The phytoplankton community could be divided into 22 functional groups, with 15 of which being representative functional groups. The representative functional groups had obvious succession among seasons (P<0.05), and the community structure had significant differences (P<0.05). Results of SIMPER analysis showed that five of the 15 representative functional groups were the main contributors to the variations of the phytoplankton community structure in the Longfeng wetland among three seasons. Redundancy analysis (RDA) of functional groups and nine water variables was performed to explore the relationship between environmental variables and the seasonal variations of functional groups. RDA results showed that electrical conductivity and water temperature were the main factors driving the seasonal variations of phytoplankton functional groups in the Longfeng wetland.

Key words: phytoplankton, functional group, temporal and spatial distribution, driving factor.