Phytoplankton functional response to spatial and temporal differences before and after the regime shift of Caohai Lake, China

-N, Sal, Tur, Cond, Chl a, TDS and TN. SIMPER analysis revealed an average dissimilarity of 53.30% in FGs between 2018 and 2023, with Lo (29.42%) and M (17.78%) contributing most to this difference. In conclusion, the aggravation of eutrophication following the regime shift was the key driver of changes in the phytoplankton community of Caohai Lake. Nutrient enrichment created a turbid, eutrophic habitat that favored the proliferation of FGs adapted to such conditions, highlighting the critical role of nutrient regulation in restoring the lake's degraded ecosystem.