Characteristics of soil filamentous fungi communities isolated from various micro−relief forms in the high Arctic tundra (Bellsund region, Spitsbergen)

Abstract

Saprotrophic filamentous microfungi were isolated by means of the soil dilution method from soil samples collected from four locations in the Bellsund region of Spits− bergen (7733'N, 1431'E) representing the following forms of surface micro−relief: an old stormbank, a sorted circle, a frost fissure between tundra polygons, and the central part of a tundra polygon. The fungal isolates were identified and screened for their ability to grow at low temperatures. The oligotrophy of psychrophilic and psychrotrophic strains was then de− termined as the ability of growth on silica gel without a C source added. Differences in some physico−chemical properties were found between the soils sampled from the four sites. A total of 89 taxa from 17 genera were isolated. Most of the isolates were species of Mortierella, Penicillium, Chrysosporium and Phialophora, and half of them were psychro− philes. Fungal communities isolated from a frost fissure between tundra polygons (site 3) and from the central part of a tundra polygon (site 4) were dominated by psychrophiles but those isolated from an old stormbank (site 1) and a sorted circle (site 2) were predominantly psychrotrophic. Oligopsychrophilic taxa accounted for 27% and oligopsychrotrophic for 20% of all the isolated taxa but only from 0.7% to 11.7% and from 1.2% to 6.3% of the total number of cfu (colony forming unit) isolated from an individual site, respectively. The re− sults of the present study suggest that the abundance of fungi in Arctic soil is mostly af− fected by the content of organic matter in the A horizon and the plant cover, but other fac− tors, such as the stage of soil development and the micro−relief of the surface, are more im− portant for species richness of fungal communities. Key wor ds: Arctic, tundra, filamentous fungi, species richness, ecology.