Effects of the Filter-Feeding Benthic Bivalve Corbicula fluminea on Plankton Community and Water Quality in Aquatic Ecosystems: A Mesocosm Study

Abstract

The influence of filter-feeding bivalves on plankton communities, nutrients, and water quality in a given aquatic ecosystem is so profound that they can be considered ecosystem engineers. In a 70-day mesocosm experiment, we tested the hypothesis that Corbicula fluminea would change plankton community structure by reducing small zooplankton and large phytoplankton and improve water quality by reducing nutrients. We monitored levels of nitrogen and phosphorus, organic suspended solids (OSS), and light at the sediment surface. Within the plankton, phytoplankton biomass (as Chl a, >0.45 μm), the biomass of microphytoplankton (>20 μm), nanophytoplankton (2–20 μm), picophytoplankton (0.2–2 μm), and zooplankton were determined. Compared with the controls, C. fluminea reduced the abundance of rotifers and the biomass of phytoplankton, and picophytoplankton, thereby modifying the plankton community structure. We did not observe reductions in TN and TP concentration, but OSS concentrations were reduced, and light intensity at the sediment surface was increased as a result of the improved water transparency. Our research shows that colonization by C. fluminea may modify plankton community structure and improve water quality of eutrophic shallow lakes, shedding further light on the ecological roles of filter-feeding bivalves in aquatic ecosystems.