INVESTIGADORES
UNREIN Fernando
congresos y reuniones científicas
Título:
Prey selectivity of mixotrophic flagellates as the main predators of picoplankton in patagonian oligotrophic shallow lakes
Autor/es:
GEREA, M.; QUEIMALIÑOS, C.; SOTO CÁRDENAS, C.; UNREIN, F.
Lugar:
Granada
Reunión:
Congreso; ASLO Meeting 2015; 2015
Resumen:
Mixotrophy by planktonic algae can dominate picoplankton predation in oligotrophic environments. We analyzed the grazing and prey preference of natural communities of mixotrophic and heterotrophic flagellates (MF and HF) through eight laboratory grazing experiments with three different sizes of natural prey (bacteria, picocyanobacteria and picoeukaryotic algae). We estimated the cell-specific grazing rate (CSGR) and grazing impact (GI) of HF and different species of MF in two oligotrophic shallow lakes. Chesson index showed that all protists preferred picocyanobacteria than bacteria, while picoeukaryotic algae were not ingested by any flagellate. In both lakes, MF were responsible of 80% of the picoplankton ingestion, showing differences in CSGR. Pseudopedinella sp. (Dictyochophyceae) exhibited the greatest CSGR (3.6 bact.flag-1h-1; 1.7 pcy.flag-1h-1) and the highest GI in both lakes. Chrysochromulina parva (Haptophyceae) and Dinobryon divergens (Chrysophyceae) were the second important predators of both picoplanktonic preys, while Plagioselmis lacustris (Cryptophyceae) showed the lowest CSGR and GI. Prey preference could be determined by the optimal size of picocyanobacteria as prey (~1µm). These results highlight the herbivory as an important process in the mixotrophic carbon recycling of oligotrophic environments.