Why predation is not a controlling factor of phytoplankton in a Neotropical shallow lake: a morpho-functional perspective

DIEGO FRAU; YAMILA BATTAUZ; RODRIGO SINISTRO

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2017 vol. 788 p. 115 - 130

0018-8158

This work explores the reasons why predation plays a minor role in structuring phytoplankton composition in a Neotropical shallow lake. Phytoplankton, zooplankton and fish were sampled from a shallow lake over the course of a year; and the stomach contents of 80 individuals of the dominant omnivorous-planktivorous fish species were analyzed. The field study was complemented with a 5 day microcosm experiment in which the predation effects of micro, meso and macrozooplankton were measured. Stomach content analysis revealed that fish predation was high, and primarily comprised by Cladocera (Ivlev´s index >0.75). Both meso and macrozooplankton fractions are able to feed on colonial cyanobacteria, silica cell-wall organisms (35 µm). Macrozooplankton, however, can feed on single cells, mucilaginous colonies, non-mucilaginous colonies and silica cell-wall organisms (>35 µm) (P