Riding the Storm: Microeukaryote Community Responses to Hurricane Disturbance.

Sandy beaches are dynamic ecosystems where terrestrial and marine organisms coexist, resulting in diverse communities where microeukaryotes (protists, microalgae, and meiofauna) are key drivers. Understanding their diversity patterns and responses to stressors is essential for elucidating ecological processes, yet information on this subject remains limited. Herein, microeukaryotic diversity in a sandy beach in Acapulco, Guerrero, was analyzed via ITS1 metabarcoding assessing community structure changes following hurricane Otis. Overall, the number of ASVs decreased substantially from 260 before the hurricane to 93 after. Groups like Porifera, Platyhelminthes, Rotifera, Amoeboza, and Choanoflagellata disappeared after the hurricane. Ochrophyta, Cnidaria, Ctenophora, and metazoans in general decreased in richness and abundance, whereas Ciliophora proliferated, particularly toward the supralittoral zone. ASVs turnover varied among zones; middle and lower coastal zones lost over 50% ASVs, and the supralittoral zone almost doubled its richness. These changes in community structure were related to total phosphorus and total nitrogen concentrations, suggesting possible bottom-up effects where nutrients available influence microbial resources for heterotrophic microeukaryotes. The observed patterns reflect high sensitivity of microeukaryotes to high-impact natural disturbances and suggest low recovery potential within the first 6 months following the event. Whether recovery occurs over longer interannual scales remains to be evaluated.