The impact of the accumulation of algal blooms on reed wetlands in the littoral zones of Chaohu Lake

In a large eutrophic lake, the littoral zone is normally an area with high-density elevated aquatic plant life, including algal blooms, where the presence of reed wetlands allows the accumulation of algae. In this study, the impact of accumulated algal blooms in reed wetlands in the littoral zones of Chaohu Lake was investigated seasonally from 2018 to 2019. The concentrations of chlorophyll a (Chl a), total nitrogen (TN), and total phosphorus (TP) were much higher in the reed-covered littoral zones (RCLZ) than in the unvegetated littoral zones (ULZ), indicating that more algal biomass was trapped and accumulated in the RCLZ. Algal biomass could be horizontally transported to downwind littoral zones under low wind speeds, favoring the establishment of blooms. Algal accumulation levels were highest in summer due to high water temperatures and algal biomasses. Likewise, the northern littoral zones were conducive to the development of large algal blooms because of the wind pattern. The values of TN, TP, Chl a, and loss on ignition in surface sediments were higher in the RCLZ than in the ULZ. Moreover, the diffusive fluxes of ammonium and soluble reactive phosphorus were also higher in the RCLZ than in the ULZ. Considering the capability of reed wetlands to trap algae, mechanical salvage and other physical methods should be adopted to eliminate algal biomass when massive blooms accumulate in the RCLZ.