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

The relationship between ergosterol content and biomass of nine species of aquatic hyphomycetes was examined. Biomass was manipulated by varying incubation period and subdividing mycelial mars. Similar results were obtained for both methods. In only three species (Flagellospora curoula, Tetrachaetum elegans and Tetracladium marchalianum) was there a significant regression between mycelial ergosterol content and biomass. Interspecific variation in ergosterol content was also evident. Consequently, 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 therefore be viewed with caution.