Effect of Anakeesta Leachate on the Decomposition of Allochthonous Leaf Litter by Aquatic Hyphomycetes

Geverd, Dawn

A thesis dealing with the effect of drainage of water through anakeesta formation and any change in the decomposition of yellow birch (Betula allegheniensis) and sugar maple (Acer saccharum) leaves that may be associated with leachate. Aquatic hyphomycetes, important regulators of detritus based ecosystems, are the first colonizers of leaf litter entering a stream. Their primary role is to breakdown complex compounds found in the leaves to more available nutrients. Streams affected by Anakeesta (a geological rock formation consisting of a pyritic carbonaceous phyllite) leachate are characteristically acidified and have high concentrations of dissolved metals. The objective of this study was to examine what effect drainage through an Anakeesta fill would have on the biomass and diversity of aquatic hyphomycetes, and to correlate these changes with decomposition for yellow birch (Betula allegheniensis) and sugar maple (Acer saccharum) leaves. Significant differences in decomposition rates, as measured by dry mass loss, were observed between yellow birch leaves placed upstream and yellow birch leaves placed downstream. The diversity of aquatic hyphomycetes growing on leaves placed upstream and downstream was also significantly different, with two different genera dominating the populations at the two sites. Articulospora was the most common genus found downstream from the Anakeesta fill, whereas Tetrachaetum was the most common genus found upstream from the Anakeesta fill. Comparisons of measures of fungal biomass were inconclusive, but appeared to indicate that fungal growth downstream from the Anakeesta fill was slower than upstream. Results from this study provide significant evidence that Anakeesta leachate has affected aquatic hyphomycetes and other organisms responsible for decomposition of leaf litter in a Southern Appalachian mountain stream.