Influence of rainfall events on zooplankton community characteristics and feeding habits in estuarine–coastal environments

Abstract

In temperate estuaries, rainfall causes environmental fluctuations, such as salinity and suspended particulate matter (SPM), and can affect zooplankton distribution patterns. This study focused on the effect of temporary freshwater inflow on the composition of major zooplankton species and changes in their ecological status in the Seomjin River estuary before (June) and after (August) rainfall in 2018. Environmental data were collected from 14 and 15 stations before and after rainfall, respectively. All factors except for chlorophyll-a (Chl-a) concentration differed significantly before and after rainfall (p<0.05), and a salinity gradient extended to Yeosu Bay from Gwangyang Bay. Zooplankton abundance decreased significantly after rainfall. There was a high correlation between indicator species abundance and environmental factors after rainfall (correlation coefficient: 0.7521); however, the indicator species and environmental factors did not exhibit a significant correlation with salinity before rainfall. In terms of feeding habit composition, the carnivore proportion showed a significant decrease after rainfall compared to before rainfall (p<0.001), while the particle feeder proportion showed a significant increase after rainfall compared to before (p<0.001). In particular, Corycaeus spp. contributed significantly to the decrease in carnivore abundance after rainfall. Among the particle feeders, Copepodites significantly increased in abundance after rainfall. Carnivore abundance was negatively correlated with salinity, and particle feeder abundance was positively correlated with potential prey sources (SPM and Chl-a concentration), suggesting that particle feeders respond to the food-rich environment after rainfall.

The Community Structure of Plankton at Floating Net Cages Aquaculture Area in Sendang Biru Water Indonesia

“…Contrary, the zooplankton abundance was found higher in October. This condition might be influenced by increasing rainfall intensity during October that led the change of zooplankton distribution pattern and feeding activities [38]. These grassing zooplankton in all sampling locations would be followed by reducing phytoplankton abundance.…”

Variation in the Occurrence of Salp and Doliolid Assemblages in the Northeastern East China Sea from 2019 to 2023

“…Moreover, the shifts in dominance between crustaceans and gelatinous filter feeders are important indicators that should be considered for long-term marine monitoring [56,57].…”