A CRITICAL-ASSESSMENT OF THE VALIDITY OF ERGOSTEROL AS AN INDICATOR OF FUNGAL BIOMASS

The relationship between ergosterol content and biomass of nine specie s of aquatic hyphomycetes was examined. Biomass was manipulated by var ying incubation period and subdividing mycelial mars. Similar results were obtained for both methods. In only three species (Flagellospora c uroula, Tetrachaetum elegans and Tetracladium marchalianum) was there a significant regression between mycelial ergosterol content and bioma ss. Interspecific variation in ergosterol content was also evident. Co nsequently, even when studying assemblages of species for which direct relationships between ergosterol and biomass occur, ergosterol could still be an unreliable measure of total biomass. This assay must there fore be viewed with caution.