The paper describes climatic conditions of the north-western part of Oscar II Land (Spitsbergen) based on meteorological data from 1975 to 2000, which were taken from Ny Alesund and Kaffioyra-Heggodden stations. The changes in annual courses of main climatic elements are investigated. However, the authors focused mainly on the analysis of summer climate, because most of the field work is conducted at this time of the year. Aside from the standard climatic analysis, the influence of atmospheric circulation on selected meteorological elements was also investigated. The climate of the north-western part of Oscar II Land was compared with the climates of the remaining areas of the western coast of Spitsbergen. It was found that the climate of the studied area differs considerably from the climate of the central-inner and southern parts of the western coast of Spitsbergen (areas represented by the Svalbard Lufthavn and Hornsund stations respectively). The differences in climatic elements, however, are not stable throughout the year and in particular seasons and months can even change signs. Thus, any generalisation of results obtained based on seasonal data is inadmissible. It was also found that the wind conditions of the Kaffioyrare- gion are more representative of the north-western part of Oscar II Land than are the wind conditions of the Ny Alesund region.
Saprotrophic filamentous microfungi were isolated by means of the soil dilution method from soil samples collected from four locations in the Bellsund region of Spitsbergen (77°33'N, 14°31'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 determined 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 results of the present study suggest that the abundance of fungi in Arctic soil is mostly affected by the content of organic matter in the A horizon and the plant cover, but other factors, such as the stage of soil development and the micro-relief of the surface, are more important for species richness of fungal communities. Key words: Arctic, tundra, filamentous fungi, species richness, ecology.
Over the last couple of years the Antarctic Peninsula region has been one of the fastest warming regions on the Earth. Rapidly proceeding deglaciation uncovers new areas for colonisation and formation of Antarctic tundra communities. The most evident dynamics, i.e. changes in both biodiversity and structure of tundra communities, are observed in the forefields of retreating glaciers. This paper presents examples of changes in biodiversity and in the direction and rate of succession changes taking place due to climate warming compounded by synanthropization in the maritime Antarctic.