Drivers of microplankton community assemblage following tropical cyclones.

This article examines the impact of Hurricane Harvey's historic freshwater discharge on coastal microplankton communities along the Texas coast, using high-resolution data from the Texas Observatory for Algal Succession Time series (TOAST) and a post-storm research cruise. The study found that while diatoms typically dominate microplankton during upwelling and mixing conditions associated with tropical storms, and dinoflagellates prevail under moderate downwelling, Hurricane Harvey uniquely triggered an unprecedented dominance of ciliates following strong downwelling and reduced salinity. Comparisons with 13 other tropical storm events over a decade revealed that such drastic shifts in microplankton composition have significant implications for biogeochemical cycling, trophic interactions, and commercial fisheries. The findings highlight the importance of physical forcing—especially freshwater discharge and current patterns—in shaping microplankton assemblages and suggest that future intensifying hurricanes may increasingly favor motile taxa like dinoflagellates and ciliates over diatoms.