Phytoplankton and Epiphyte Development and Their Shading Effect on Submerged Macrophytes in Lakes of Different Nutrient Status

Authors:
Publisher website
Google Scholar
Abstract
The annual mean light intensity at the depth limit of the Littorella vegetation was 24–33% of the subsurface light intensity, despite large variations in each attenuation component (lake water, phytoplankton, and epiphytes). In oligotrophic, silicate‐poor lakes, the light attenuation above the submerged vegetation was dominated by the water itself, which accounted for 65–72% of the total attenuation. Phytoplankton and epiphytes were equal in importance to each other. In oligotrophic, silicate‐rich lakes and lakes receiving a nitrogen supply above background level, the epiphytes were more abundant, accounting for about 50% of the light attenuation. In one lake with a high nutrient supply, the epiphytes were responsible for 86% of the light attenuation.A new method of measuring the effect of shading by the epiphytic community on submerged macrophytes is presented. The light attenuation caused by the phytoplankton and the epiphytes was investigated and related to the depth distribution of the submerged angiosperm, Littorella uniflora.It is shown that the biomass of the epiphytes increased more than the biomass of the phytoplankton in response to an external or internal nutrient loading. Shading by epiphytes is of decisive importance for the depth distribution of Littorella at increasing nutrient supply.

This publication has 37 references indexed in Scilit: