Effect of an invasive filter-feeder on the zooplankton assemblage in a coastal lagoon

O. IRIBARNE,; BRUSCHETI, M.; LUPPI, T

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2016 vol. 96 p. 1201 - 12010

0025-3154

Depletion of phytoplankton biomass by the introduced reef-forming polychaete Ficopomatus enigmaticus has previously beenobserved in the Mar Chiquita lagoon (37840′S 57823′W; Argentina), but the effect of polychaetes on the higher trophic levels isstill unknown. To evaluate the effect of this polychaete on the zooplankton assemblage, replicated mesocosm experiments(N ¼ 10) were performed during spring, summer and winter. Mesocosms with reefs and without reefs were installed andgrazing intensity and the effect on the zooplankton assemblage by the polychaetes were assessed. Our results show that thereefs of F. enigmaticus generate minor changes in overall composition of zooplankton assemblage. Although the structureof the zooplankton assemblage was different between seasons, the impact of the reefs was not significant in any of them.There was no relationship between the decline of food resource by grazing and changes in the structure of the zooplanktonassemblage. Thus, contrary to our hypothesis, the grazing impact of the invasive polychaete on the biomass of primary producersdid not generate cascading effects to higher trophic levels. However, changes in some components of the zooplanktonassemblage (e.g. cladocerans) clearly show that the reefs of F. enigmaticus have the potential to affect the structure of thezooplankton community. The lack of data of community composition and abundance of zooplankton before the invasionlimits the understanding of how this polychaete might have affected the structure and abundance of the zooplankton ofthis lagoon. Nevertheless this work suggests that these changes may not be so significant.