Studies were performed in the summer of 1989 in the vicinity of the Polish Polar Station at Hornsund, Svalbard, in an attempt to characterize the functioning of selected tundra soils in terms of bioenergetics. The intensity of bioenergetical processes in the soil was evaluated by the rates of O2 consumption and CO2 production, measured in the laboratory under controlled hydrothermic conditions. Soils metabolic processes are markedly correlated with soil water content and dependent upon soil structure, water capacity and character of plant cover. The strongest correlation was observed in the more aerated soils with small water capacity and without vegetation. The respiratory quotient (RQ) decreased with the growth of soil moisture content. Soil metabolic activity began directly after the summer melting of the ground, when the soil temperature reached 0°C, and ceased in autumn, when temperatures fell below 0°C again.
In the Fugleberget catchment area (Spitsbergen, Hornsund Fiord region) the growing season lasted 95 days, with growth beginning under the snow. In this time shoots of moss Calliergon stramineum reached a mean length of 19 mm and mean biomass of 0.593 mg dry weight. Annual primary production of moss communities amounts to 220-270 g dry weight per square meter per year. In the first year of destruction the dead plant material lost 30-45% of its initial value, after 10 years only ca 25% of the initial amount of organic matter was left.
The annual rate of decomposition in five soil types of tundra situated in the Fugleberget drainage area (Hornsund Fjord, South Spitsbergen) was investigated by use of the method of standard cellulose samples. The rate of decomposition varied from 15% to over 65% a year and was closely connected with a contents of nitrogen in soil, amount of which varied from 0.33% to 3.44%. The results presently obtained are much higher than those obtained by the same method in other polar regions.
Soils of Russian European North were investigated in terms of stability and quality of organic matter as well as in terms of soils organic matter elemental composi-tion. Therefore, soil humic acids (HAs), extracted from soils of different natural zones of Russian North-East were studied to characterize the degree of soil organic matter stabilization along a zonal gradient. HAs were extracted from soil of different zonal environments of the Komi Republic: south, middle and north taiga as well as south tundra. Data on elemental composition of humic acids and fulvic acids (FAs) extracted from different soil types were obtained to assess humus formation mechanisms in the soils of taiga and tundra of the European North-East of Russia. The specificity of HAs elemental composition are discussed in relation to environmental conditions. The higher moisture degree of taiga soils results in the higher H/C ratio in humic substances. This reflects the reduced microbiologic activity in Albeluvisols sods and subsequent conser-vation of carbohydrate and amino acid fragments in HAs. HAs of tundra soils, shows the H/C values decreasing within the depth of the soils, which reflects increasing of aromatic compounds in HA structure of mineral soil horizons. FAs were more oxidized and contains less carbon while compared with the HAs. Humic acids, extracted from soil of different polar and boreal environments differ in terms of elemental composition winch reflects the climatic and hydrological regimes of humification.
Ornithogenic tundra developing near large seabird colonies with its dense vegetation creates sites for foraging, hiding and breeding of herbivores. Grazing, trampling and faeces deposition are considered as the most important ways that vertebrate herbivores influence the plants. Excrement deposition level informs us on the intensity of grazing i.e. foraging ground attractiveness. We have compared vertebrate herbivores’ faeces deposition (biomass) in the vicinity of big colonies of piscivorous (kittiwake Rissa tridactyla and Brünnich’s guillemot Uria lomvia) and planktivorous (little auk Alle alle) seabirds and the control area was in Hornsund, SW Spitsbergen. Much higher level of faeces deposition was recorded nearby seabird colonies as compared to the control area. These finding points out that vertebrate herbivores concentrate and feed more intensively on rich ornithogenic pastures. Number of herbivores and their faeces deposition level recorded nearby planktivorous seabird colony were greater as compared to those found nearby the colony of piscivores. The highest number of geese (Branta bernicla and Anser brachyrhynchus) and of their faeces biomass were found near the colony of planktivorous little auk, where distinct gradient in faeces deposition level along the colony-seashore axis was recorded. Reindeers Rangifer tarandus were observed in considerable numbers near the little auk colony, and were not recorded at all near cliff-nesting sites of kittiwakes and guillemots. Total deposition of excrements produced by geese was generally higher if compared to reindeers.
Species diversity of Collembola was studied in the vicinity of Polish Polar Station, Hornsund area, West Spitsbergen. A list of 32 species has been compiled, and their distribution over microlandscapes and microhabitats in the study area has been presented.
Communities of soil invertebrates were studied in 4 types of tundra ecosystems on Spitsbergen (Hornsund area) during the vegetative season of 1989. Taxonomic composition, density and biomass of soil fauna were evaluated in the sites along a gradient of increase in the biogenic impact of bird colonies, i.e. in polygonal tundra, mossy/lichenous tundra, Calliergon stramineum moss association, and mossy associations near a colony of Little Auks (Alle die). Average total biomass of soil invertebrates increased in this site sequence from 1.1 to 25.0 g wet weight x m-2 (mainly due to collembolans and nematodes). Seasonal dynamics of all groups of soil meso- and macrofauna (Nematoda, Enchytraeidae, Aranei, Acarina, Collembola, Coleoptera, Diptera larvae) is presented and discussed.
On the basis of a year-long series of actinometric measurements performed in the vicinity of Polish Polar Station at Hornsund, this paper presents the characteristic of the value of solar radiation incoming at the active surface, of absorbed and net radiation. The maximum intensity of the direct solar radiation was 822 Wm-2, the annual sum total of total radiation was 2611 MJm-2, whereas the mean yearly albedo was 59%. The zero-crossing of the 24-hour sums of the net radiation towards negative values occurred at the turn of September and October.
In surface horizons of Gelic Regosols. Gelic Gleysols and Gelic Cambisols from 5 sites in Kaffiöyra. 26 taxa of blue-green algae have been determined. Species of the genera Gleocapsa, Schizothrix, Tolypothrix and Calothix were the most common. In Gelic Regosols blue-green algae formed during the last 100 years the 0.5 cm thick horizon A, containing 8.6% of humus.
Physical and chemical properties (granulometric composition, pH, carbonates, organic carbon, nitrogen etc.) as well as bioenergetic activity of Spitsbergen tundra soils were studied at three chosen stations situated near Polish polar station "Hornsund". It was found that biological activity of Arctic tundra soils depended mainly on its physical properties, whereas the chemical composition of organic matter did not effect directly the bioenergetics of these soils. This bioenergetic activity depends mainly on the richness of micro- and mesofauna communities inhabiting the soil.
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 psychrophiles. 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.
Solar radiation reflectance was analysed to characterize Arctic ornithogenic tundra developing in the vicinity of large breeding colony of Brunnich‘s guillemots Uria lomvia and kittiwakes Rissa tridactyla at the foot of Gnĺlberget cliff (Hornsund, SW Spitsbergen). Radiometric method was found to be a useful tool for studying structure and functioning of plant formations. We measured reflectance of four wavelengths: 554 nm (YG), 655 nm (RED), 870 nm (NIR) and 1650 nm (SWIR) at 10 plots situated along the transect running from the colony to the sea. Moreover, data of plant community character, species quantitative composition as well as total biomass were collected to relate these parameters with the spectral values. The results showed that radiometric data characterized vegetation well enough to recognize the same plant communities on the basis of spectral reflectance as distinguished with traditional phytosociological methods.
The avifaunistic observations carried out in the tundra valley of the Sob River's upper course (west slopes of the Polar Ural) in July 1995 revealed the occurrence of 39 breeding and 8 non-breeding bird species. The most numerous were Anthus pratensis, Calcarius lapponicus, Phylloscopus trochilus and Anthus cervinus. The great variety of wetland and aquatic habitats had a decisive influence on species-richness and abundance of birds (jointly 30 breeding and 4 non-breeding species). Areas of low humidity were inhabited by 14 whereas anthropogenic habitats by 4 species. Most of them (except for eurytopic A. pratensis and C. lapponicus) occupied one-two habitats irrespective of their numbers. The density of Buteo lagopus was estimated at 1.67-2.00 p/10 km2. Three species of distribution ranges laying to the south from the study area, namely Bucephala clangula, Dendrocopos major, Circus macrourus, were noted in the valley. The results obtained have been compared with available data on the avifauna of the region concerned.
Humification plays an important role in stabilization of organic matter in soils of the cryolithic zone. In this context, the degree of organic matter stabilization has been assessed, using instrumental methods, for permafrost peat soils of the eastern European Arctic, based on selected plots from within the Komi Republic (Russian Federation). Humic substances (HSs) isolated from the mire permafrost peats of the forest-tundra subzone of the European Arctic have been characterized in terms of molecular composition. This was accomplished using elemental and amino acid fragments (AAFs) composition. Solid-state 13C nuclear magnetic resonance (13C NMR) spectroscopy was utilized to identify the structure of HSs. Changes in the molar x(H) : x(C) ratio, ratio of aromatic to paraffin fragments and ratio of hydroxy AAFs to heterocyclic AAFs along the peat profiles have been revealed. They are due to the activation of cryogenic processes in the upper part of the seasonally thawing layer, the natural selection of condensed humic molecules, the botanical composition and degree of degradation of peat, which reflect the climatic features of the area in the Holocene. Humic acids and fulvic acids of the peat soils showed the prevalence of compounds with a low degree of condensation and a low portion of aromatic fragments. The aromaticity degree showed the trend to increase within the depth. Changes of quantitative and qualitative parameters of specific organic compounds occur at the permafrost boundary of peatlands, which can serve as an indicator of recent climate changes in environments from the high latitudes. The presented data can be useful in the evaluation of soil organic matter stabilization degree in the active layer and below the permafrost table.