The effect of an invading filter-feeding bivalve on a phytoplankton assemblage from the Paraná system: a mesocosm experiment

DIEGO FRAU; FLORENCIA ROJAS MOLINA; MELINA DEVERCELLI; SUSANA JOSÉ DE PAGGI

MARINE AND FRESHWATER BEHAVIOUR AND PHYSIOLOGY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2013 vol. 45 p. 303 - 316

1023-6244

The effect of different concentrations of the bivalve Limnoperna fortunei onthe algal density and structure and its filtration rate was estimated in amesocosm experiment. The experiment was carried out using containers of200L and three treatments: Control (without bivalves), C1 (with 128individual bivalves), and C2 (with 256 individual bivalves). Decrease inphytoplankton density was detected in bivalve treatments after 6 h.A decrease of 52% and 86% of the initial density was measured in C1and C2, respectively, after 48 h. All algae groups showed substantialdecrease in densities (460%) and the composition of the algae assemblageschanged in the presence of the bivalve. In particular, there was an increasein the density of Flagellates. The maximum estimated bivalve filtration ratewas 357mLind1 h1 at 28C. Our results suggest that the invadingbivalves could significantly affect both the plankton density and assemblagestructure in natural systems.