Competition between pelagic and benthic microalgae for phosphorus and light

In freshwater ecosystems production of both pelagic and benthic microalgae tends to be limited by phosphorus and light. However, the availability of these resources to pelagic and benthic communities differs due to differences in habitat structure. In a well mixed epilimnion individual phytoplankton cells should receive similar light intensities and nutrient concentrations per unit time. Benthic microalgae colonize substrates forming three-dimensional mats. Their access to nutrients and light is partially determined by the vertical architecture of the mat and often restricted to the canopy layer algae. In addition, algal mats will always be shaded by the phytoplankton inhabiting the water column above.