Epsilon Archive for Student Projects

Abstract

Many studies on global elements fluxes neglect biological aspects or simply refer to them unspecifiedly as biological activity. The advent of molecular tools to investigate these ac-tivities has although given rise to a further understanding of the matter. In this study an attempt to determine the ecology and function of 11 strains of the fungal genus Leptodon-tidium (L.) in boreal forest soils is made. In an earlier study (Lindahl et al. 2010) strains with affinity to L. increased in abundance after the disruption of root carbon transport from host trees to ectomycorrhizal Fungi. At the same time ectomycorrhizal species de-creased in abundance which provoked the hypothesis that the senescent ectomycorrhiza is decomposed by L. and other opportunistic Fungi. To test this hypothesis L. strains were grown on different agar based substrates while substrate utilization was assessed by measuring respiration. Since other studies observed increased soil ammonium levels in disturbed forests (e.g. clear cut areas) another experiment was set up to measure ammo-nium mineralization of L. when decomposing fungal substrate. Finally a phylogeny of the strains based on the rDNA internal spacer and large subunit region was made in order to get more information on taxonomic relationships as well as ecological and functional in-formation.