Effects of Corbicula fluminea on the nutrient concentration and phytoplankton biomass of tropical reservoirs

Abstract

Invasive bivalves are known to negatively impact aquatic ecosystems across the globe. Previous research has demonstrated invasive bivalves can shift nutrients from the water column to the sediment, harm native bivalves, and reduce phytoplankton biomass. However, bivalve effects vary with species and the region where the invasion occurs. Therefore, we used mesocosm experiments to examine the impact of invasive <em>Corbicula fluminea</em> on nutrient concentration and phytoplankton biomass in the water column of mesotrophic and eutrophic Puerto Rican reservoirs. We used four treatments to determine the effect of <em>C. fluminea</em> on the water column. We found <em>C. fluminea</em> did not have a significant effect on the ammonium, nitrate, or phosphorus concentration in either the mesotrophic or eutrophic mesocosm experiments. Additionally, <em>C. fluminea</em> presence did not significantly alter phytoplankton biomass, though <em>Synedra</em> dominated the phytoplankton community when <em>C. fluminea</em> were absent. While <em>C. fluminea</em> may not have caused an effect in the water column as it was potentially phytoplankton limited, the mesocosm experiment conditions reflect the natural environment, indicating phytoplankton limitation could be an issue in the reservoirs. Our findings suggest <em>C. fluminea</em> does not have a large effect on nutrient concentration or phytoplankton biomass in eutrophic and mesotrophic Puerto Rican reservoirs. This study represents the first effort to examine the effects of <em>C. fluminea</em> presence on the water column of a tropical reservoir.