Responses of reservoir phytoplankton biomass stability to environmental changes under high-frequency monitoring

The temporal stability of phytoplankton community is critical for the stable provisioning of primary production in aquatic ecosystems. However, it remains poorly understood how the phytoplankton community stability responds to environmental dynamics in subtropical reservoirs at a finer temporal scale. We collected phytoplankton and water samples every ten days in Tingxi Reservoir, subtropical China from April 2015 to January 2020. We examined the synchrony-biodiversity-biomass stability relationships of reservoir phytoplankton. Further, we investigated the driving factors and elucidated the maintenance mechanisms of phytoplankton biomass stability. We found that 1) temporal synchrony and community dissimilarity significantly reduced phytoplankton biomass stability, and 2) non-significant species richness-stability relationship, which is not consistent with more diverse communities making greater stability. Our results revealed that asynchronous responses to environmental dynamics help maintain phytoplankton biomass stability. Our study helps to enhance understanding of synchrony-biodiversity-stability relationships and to clarify the response mechanism to environmental change of phytoplankton community.