Seasonal and spatial dynamics of mesozooplankton community in a subtropical embayment

Mesozooplankton abundance and community composition are influenced by hydrography and biological interactions. In subtropical systems influenced by seasonal monsoons, seasonal cycle of plankton communities could be disrupted and restructured by short but intense weather events. Our survey of a shallow subtropical embayment to the northern part of the South China Sea demonstrated temporal variations in zooplankton biomass and composition between monsoon periods: not only were the wet (summer monsoon) and dry (winter monsoon) periods distinctive from each other, but also the transition phase between the two. The meroplankton communities were distinct between the monsoon periods with fish, decapods and echinoderm peaked during the wet season and cirripedia bloomed in dry season. This pattern can be attributed to both changes in growth conditions and influx of individuals through monsoon-driven water currents. The community shift during the transitional phase, defined by the rapid changes in salinity and temperature, corresponded to the reported reproductive cycles of marine organisms, including commercially important fishes, crustaceans, and echinoderms. The interannual variability observed during the wet period reflected changes in rainfall between consecutive years, highlighting the importance of having a long time series with which to establish a baseline information to better manage nursery habitats like the one surveyed, particularly in light of increasing coastal development. Subtropical coastal zooplankton communities are highly dynamic with multiple pulses and interruptions driven by weather events.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Mesozooplankton abundance and community composition in subtropical systems are influenced by hydrography and biological interactions. The study found temporal variations in biomass and composition of zooplankton between monsoon periods, including the transitional phase. The community shift during the transition phase corresponds to the reproductive cycles of marine organisms. The interannual variability observed during the wet period highlights the importance of long-term data for managing nursery habitats in light of coastal development.