Quantifying the effects of wind wave on cyanobacterial blooms in large shallow lake from 10 years high frequency satellite observation

Wind deeply impacts the short-term temporal-spatial dynamics of cyanobacterial blooms in large, shallow and eutrophic lakes, but the quantitative contributions of wind wave to cyanobacterial blooms remain unclear. In this study, we assessed the frequency of surface cyanobacterial blooms, in response to wind wave in Lake Taihu, China, based on high-frequency hourly GOCI images and long-term meteorological, hydrological and ecological environment records from 2011 to 2020. Results showed marked monthly and seasonal variabilities of cyanobacterial blooms frequency with two peaks in summer and autumn. Spatially, the prevailing wind directions from summer to winter, shifting from southeast to northwest winds, promoted the downwind horizontal drift and accumulation of surface cyanobacterial blooms from northwest to southwest in Lake Taihu. Moreover, we found significantly negative correlations between wind wave and cyanobacterial bloom frequency, particularly during the cyanobacterial bloom growth season from April to November. Further analysis revealed the determining role of wind wave in controlling cyanobacterial bloom dynamics in Lake Taihu, with contributions of 62.12% and 57.63% in spring and summer, respectively. Our findings offer an important scientific insight for the effective collection of harmful blooms in inland freshwater lakes under both nutrient management and climate change scenarios.