Periphyton in Lakes of Different Trophy

Abstract

In a study of 10 lakes in the Eastern Townships (Quebec) periphyton biomass correlated less well with total P (TP) concentration in the water than did phytoplankton biomass. The relationship with TP was improved somewhat when periphyton biomass was estimated as cell volume rather than as chlorophyll or organic material. When the community was divided among various groups according to taxa, life form, and size, only the biomasses of greens, filamentous algae, and algae exceeding 10 000 μm3 were correlated with TP. The biomass of the smaller algae, which are more readily grazed by benthos, was about the same in all lakes whereas nuisance forms increased significantly with P enrichment. At more eutrophic sites, maximal periphyton biomasses were observed in midsummer, coinciding with peak recreational use of lakes, whereas at the other sites, maxima appeared earlier in the season.