The properties of Daphnia carinata King as a grazer for use in biomanipulation trials were investigated.
Mesocosm experiments suggested that in water from a lake where D. carinata was scarce,
phytoplankton was nutrient-limited and the manipulated biomass of zooplankton had no effect on total
chlorophyll a, whereas in water from a lake where D. carinata was dominant, nutrients were not
limiting and total chlorophyll a was negatively correlated with the manipulated biomass of zooplankton.
When offered lake phytoplankton in feeding trials, D. carinata consumed all items present, including
colonies of cyanobacteria and long filaments of diatoms. In large outdoor tanks with natural plankton,
the biovolume of prokaryotic ultraplankton (possible predecessors of cyanobacterial blooms) was
consistently reduced in the presence of D. carinata. There was no evidence of an adverse effect of
single-celled Microcystis aeruginosa containing the peptide toxin microcystin-LR on D. carinata
grazing rates or survival. Different concentrations of microcystin-LR in solution covering the range of
toxicities observed during M. aeruginosa blooms (5-500 nM) had no effect on D. carinata grazing. The
suppression of phytoplankton biomass by D. carinata grazing is one of several possible mechanisms
that might be considered for biomanipulation in Australia.
The effects of microcystin‐LR in
Oryza sativa
root cells: F‐actin as a new target of cyanobacterial toxicity
