The stimulation of phytoplankton growth by an invertebrate predator

Murray-Darling Freshwater Research Centre

MDFRC item.

In experimental microcosms with water from two lakes of different productivity, carnivorous planktonic water mites Piona australica Viets prefed with Daphnia directly simulated the growth of most algae present. In the experiments, the biovolumes of individual species of algae and their total biovolumes were positively correlated with manipulated water mite density. Water mites enhanced the growth of increasing populations of algae and made declining populations start growing. This stimulation was apparently mediated through predators’ excreta.