Abstract Despite the pivotal role of fungi in regulating algal blooms and ecosystem health, community-level fungal dynamics in natural cyanobacterial bloom events, and their correlation with changes in algal communities, remain poorly understood. Through a year-long survey in eutrophic Lake Chaohu, China, we analyzed the planktonic fungal and phytoplankton community changes. The results showed that Chytridiomycota dominated the fungal community throughout the year, whereas Ascomycota and Basidiomycota increased markedly during late-bloom and post-bloom periods, suggesting a functional shift from potential parasitism to saprotrophy. Algal and fungal communities showed significant concordance at the community level, as indicated by the positive relationship between their Bray–Curtis distances (P 0.001). Separate fitting of dominant algal taxa onto the fungal ordination space showed that Microcystis was primarily associated with the bloom-period fungal assemblage, whereas Chlorella and others were more closely associated with non-bloom fungal community variation. The strength of algal–fungal associations also increased significantly with the relative dominance of algal taxa (P 0.05), supporting a dominance-dependent interaction pattern. Together, these results indicate that planktonic fungal communities were closely associated with algal community dynamics through both host-abundance- and host-dominance-related patterns, and highlight the importance of considering fungal processes in ecological frameworks for understanding phytoplankton succession and cyanobacterial bloom dynamics.
Zhang et al. (Tue,) studied this question.