UBC Theses and Dissertations
Hyphomycetes from sediments of Marion Lake, British Columbia Chang, Yola Chiou-Yueh
Geofungi, mainly Hyphomycetes, are important members of aerobic aquatic habitats. The occurrence, distribution and seasonal variation of Hyphomycetes in Marion Lake sediments were studied, using a modi-, fied dilution plate method. The maximum number of viable fungi occurred during the winter. The highest fungal count as well as the largest number of fungal species was found in the deeper-water muds. The pattern of spatial and seasonal variations of fungi is interpreted as the result of the combined action of many factors, such as, temperature, pH and organic matter content of the muds, rain-fall and other microorganisms, all of which affected the pattern to different degrees and at different times. This study shows that there is a sizable and diverse population of Hyphomycetes in Marion Lake sediments. Seventy-three species and species groups, excluding Penicillium species, belonging to 39 genera were isolated and identified. The taxonomy, morphology, ecology and physiology of some of these Hyphomycetes are briefly reviewed. (?)Humicola sp., Penicillium, Trichoderma and hyaline and dark Mycelia Sterilia were the most common fungi. As determined by the agar-diffusion method, 32 of the 36 species and varieties of Hyphomycetes tested exhibited cellulolytic ability. Trichoderma was the strongest cellulose decomposer. Fungal activity in situ also was investigated, being based on observations of cellophane decomposition in the lake muds. In the process of cellophane breakdown, as determined by direct microscopy, cultural isolation and scanning electron microscopy, there was an indication that fungi are more important decomposers than either bacteria or actinomycetes The Hyphomycetes isolated from buried cellophane were the same species recorded as dominant fungi when the modified dilution plate method was use for isolation. Thus, it is implied that these Hyphomycetes are significantly responsible for the decomposition of cellulose in Marion Lake muds.
Item Citations and Data