The Effect of an Invading Filter-Feeding Bivalve on a Phytoplankton Assemblage from the Paraná System: A Mesocosm Experiment

FRAU, D., ROJAS MOLINA, F., DEVERCELLI, M., JOSÉ DE PAGGI, S.

MARINE AND FRESHWATER BEHAVIOUR AND PHYSIOLOGY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2012

1023-6244

The effect of different concentrations of the bivalve Limnoperna fortunei on the algal density and structure and its filtration rate was estimated in a mesocosm experiment. The experiment was carried out using containers of 200L and three treatments: Control (without bivalves), C1 (with 128 individual bivalves), and C2 (with 256 individual bivalves). Decrease in phytoplankton density was detected in bivalve treatments after 6 h. A decrease of 52% and 86% of the initial density was measured in C1 and C2, respectively, after 48 h. All algae groups showed substantial decrease in densities (460%) and the composition of the algae assemblages changed in the presence of the bivalve. In particular, there was an increase in the density of Flagellates. The maximum estimated bivalve filtration rate was 357mLind1 h1 at 28C. Our results suggest that the invading bivalves could significantly affect both the plankton density and assemblage structure in natural systems. Keywords: mussel; invasive; Limnoperna fortunei; phytoplankton; species selectivity; filtration rate; mesocosm