Spatiotemporal variation of marine microbes in the Taiwan strait ecosystem

The impacts of extreme climate events and human activities on coastal ecosystems have attracted increasing attention, while the effects on microbial dynamics in the vertical water ecosystem across seasons, particularly under the influence of typhoon, fishing, and shipping disturbances in the strait ecosystems, remain unclear. Through systematic sampling, nutrient analysis and 16S rRNA gene amplicon sequencing, we investigated the spatiotemporal dynamics and functional fluctuations of marine microbes in the Taiwan Strait. The results revealed distinct seasonal variations in both environmental niches and microbial compositions. The proportional variation of Cyanobacteria, Crenarchaeota and Bacteroidota across water layers plays a crucial role in maintaining the stability of the strait ecosystem under extreme natural and anthropogenic disturbances. The carbon fixation and ammonia oxidation processes, associated with microorganisms such as Synechococcus CC9902, Candidatus Nitrosopelagicus, and Candidatus Nitrosopumilus, exhibited seasonal changes, while the NS4 marine group, Phalacromamitra, Teleaulax amphioxeia, and Neptuniibactercaesariensis displayed vertical fluctuations. Natural events and human activities significantly affected microbial community assembly across seasons and depths by altering microenvironmental properties and nutrient concentrations. Dominant species such as Alteromonasmacleodii, Alpha proteobacterium HIMB59 and Alpha proteobacterium HIMB114 adjusted their degradation efficiency according to nutrient concentrations to maintain ecosystem stability. The findings enhance our understanding of how keystone microorganisms respond to natural and anthropogenic events in the strait ecosystem.