Held, Benjamin William2014-09-052014-09-052013-07https://hdl.handle.net/11299/165417University of Minnesota Ph.D. dissertation. July 2013. Major: Plant Pathology. Advisor: Robert A. Blanchette. 1 computer file (PDF); viii, 99 pages.Compared to other biomes, very little is known about fungal diversity in Antarctica and how these important organisms function in this unusual ecosystem. The studies presented in this dissertation are focused on the fungi found in wood on Deception Island (an active volcano), Antarctica, their phylogenetic diversity and role as important decomposers in the polar environment. A diverse fungal assemblage of known wood decay fungi is reported from historic wood in structures at Deception Island, Antarctica as well as the discovery of several undescribed species. The major group of wood decay fungi found was Cadophora species which have been found in other geographic regions of Antarctica causing a soft-rot type of decay in introduced woods. Unlike other areas of Antarctica that have been studied, several filamentous basidiomycetes (Hypochniciellum spp. and Pholiota spp.) were also identified that have different modes of degradation including brown and white rot. The conservation of these historic structures poses difficult challenges because of their polar location and geothermal activity. Lahars have partially buried many of the structures. The buried environment and moist, warm soils are conditions conducive for fungal growth facilitate deterioration by the fungi described. In addition, the diverse assemblage of decay fungi add to the difficulty of conserving these important polar heritage sites. A number of studies have identified Cadophora species, mainly in association with wood, from many areas of Antarctica. A phylogenetic study using four gene regions identifies a diverse group of Cadophora spp. present at different sites in Antarctica (Ross Sea, Peninsula). Cadophora malorum, C. fastigiata sensu stricto, and C. luteo-olivacea were very similar phylogenetically in these gene regions. Undescribed species were also discovered that were closely related to C. fastigiata. Decay studies showed that nearly all the species were able to cause a soft rot type of decay in birch wood wafers and were able to tolerate high levels of salt and copper sulphate. These studies support information that Cadophora spp. are well adapted to thrive in extreme conditions and appear to be important decomposers in these biomes.en-USAntarcticaDeception IslandFungal diversityHistoricWood decayThesis or Dissertation