Herbivory by zooplankton could result in a change in algal biomass, diversity or species composition. Large cladocerans (e.g. Daphnia) are very efficient filter feeders and have been demonstrated to be capable of substantially reducing algal biomass. More diverse zooplankton communities would produce greater algal diversity because of more diverse diets.
The species composition of the algal can be altered by selective herbivory on edible vs non-edible algae. Therefore a lake that has an intense and diversified grazing pressure would show decreased algal biomass, increased pigment diversity and could have an increase in the ratio of inedible to edible algae.
Intense predation by fish will selectively remove the larger zooplankton. Invertebrate predators have an inverse effect on community size structure in that predacious invertebrates select smaller prey that are easily handled. The relative importance of invertebrate and vertebrate predation can be detected by observing the size and shape of Cladocera. For example, "long-forms" of Bosmina have long spines and antennules which makes them more adept at escaping copepod predators.