Coupling between environmental drivers and microbial networks in shaping marine plankton dynamics

Marine plankton are ecologically crucial, as they contribute to biogeochemical cycles and food web structure. This study investigated the structure and dynamics of marine plankton communities in relation to local environmental conditions and seasonal changes over 2 years in the coastal regions of Busan, Jinhae, and Masan in South Korea. The results revealed significant variations in the plankton community composition between Jinhae/Masan and Busan, driven by freshwater inputs, temperature fluctuations, and salinity changes. Dinoflagellates predominated the plankton communities of Jinhae and Masan, whereas high abundances of diatoms, cyanobacteria, and cryptophytes were found in Busan. In addition, seasonal dynamics were observed in microbial abundances, with cyanobacteria and diatoms predominating during summer when water temperatures were elevated, and two distinct blooms occurring in winter. The plankton community correlated with environmental variables and organisms, resulting in either co-clustering or niche segregation. Additionally, bacterioplankton and phytoplankton formed complex networks with each other. Our findings emphasize the interplay between abiotic and biotic factors in shaping plankton community structures and underscore the need for comprehensive studies integrating environmental monitoring with analyses of interspecies interactions. This research enhances our understanding of the dynamic changes in marine plankton communities and provides a valuable basis for future marine ecosystem management.