Microorganisms colonizing plants and soil subjected to different degrees of human activity, including petroleum contamination, in the Vestfold hills and MacRobertson Land, Antarctica

Summary

The fungal floras of plant communities and mineral soils were determined at locations both close to and away from sites of human activity. Petroleum contaminated soils and discarded wood which occur near Stations were also studied, the former for bacterial as well as fungal colonization. The fungal floras of uncontaminated natural communities comprised relatively few species, Geomyces pannorum, Phoma herbarum and Thelebolus microsporus being the most common, together with Epicoccum nigrum at Mawson. P. herbarum dominated the fungal floras of mosses at Mossell Lake but E. nigrum was also common in Mawson mossbeds. G. pannorum was widespread and colonized a range of different habitats, particularly in the Vestfold Hills. T. microsporus was also widespread particularly at sites frequented by birds and seals. Phialophora fastigiata was common around the Stations, especially Davis Station, in soils including those contaminated with oil and in wood, and is thought to have been introduced with softwood packing crates. A greater range of taxa including Mortierella, Mucor, Penicillium and Cladosporium spp. was recorded from Mawson Station than from other sites, and this was attributed to the effects of human activity. Few fungi but a range of bacteria were isolated from the petroleum contaminated soils. A high percentage of these soils contained bacteria which could utilize hydrocarbons as a sole carbon source. Some of these bacteria showed a strong degradative potential, namely Flavobacterium spp., Corynebacterium spp., Bacillus spp. and an isolate from the family Enterobacteriaceae. One isolate of Corynebacterium and the Enterobacteriaceae isolate were active hydrocarbon degraders at 1°C. Hormoconis resinae, the imperfect state of Amorphotheca resinae was only isolated from oil spill soils and then only from sites of recent spills. Geomyces pannorum and Thelebolus microsporus were less common in oil contaminated soils than in uncontaminated soils.