In this article, the results of an investigation into the air temperature conditions on Svalbard in the period 1 September 2010 to 31 August 2011 are presented. For this period, parallel temperature measurements have been made as many as in 30 sites. On the basis of this unique set of data it was possible to study, in detail, the spatial distribution of different thermal characteristics [mean temperature, diurnal temperature range (DTR), day‐to‐day variability, degree of climate continentality, etc.] in Svalbard. Such knowledge of the whole of Svalbard was not previously available with sufficient accuracy for all areas. High resolution maps showing the spatial distribution of all studied thermal characteristics were also produced and analysed. Analysis of surface temperature data shows that the markedly coldest area throughout the whole year was northern Svalbard, and in particular its eastern side (Nordaustlandet). On the other hand, the highest temperatures were recorded in western part of Spitsbergen. The greatest spatial decreasing rate of temperature in Svalbard throughout the whole year was observed in a southwest (SW)–northeast (NE) direction. The distribution of mean seasonal and annual temperature reduced to sea level on Svalbard differs from the distribution based on surface temperatures. Spring, and in particular winter, saw the greatest DTRs (4–7 and 6–9 °C, respectively), while the lowest were observed in summer (3.0–3.5 °C). In all seasons, the highest DTR were mainly noted in the NE part of Svalbard, while the lowest were in its SW part. The lowest continentality of climate (30%) is clearly seen in the south‐western part of Svalbard, while the highest values (above 43%) stretch from the western part of Nordaustlandet to the area of Sveagruva in the central‐eastern part of Spitsbergen. The NORA10 hindcast temperature data differ significantly from measured data for some seasons and areas and need bias corrections when used in climatology.

The cadmium (Cd 2? ) and lead (Pb 2? )-induced changes in Cu,Zn-SOD gene expression on the level of mRNA accumulation and enzyme activity were analyzed in roots of soybean (Glycine max) seedlings. The Cd 2? caused the induction of copper-zinc superoxide dismutase (Cu,Zn-SOD) mRNA accumulation, at each analyzed metal concentration (5-25 mg/l), whereas in Pb 2? -treated roots this effect was observed only at the medium metal concentrations (50-100 mg/l of Pb 2? ). The analysis of Cu,Zn-SOD activity proved an increase in enzyme activity during Cd 2? /Pb 2? stresses, however in Pb 2? -treated plants the activity of enzyme was not correlated with respective mRNAs level. Presented data suggest that different metals may act on various level of Cu,Zn-SOD expression in plants exposed to heavy metals stress.

Cadmium (Cd), similarly to other heavy metals, inhibits plant growth. We have recently showed that Cd(2+) either stimulates (1-4 microM) or inhibits (>or= 6 microM) growth of soybean (Glycine max L.) cells in suspension culture (Sobkowiak & Deckert, 2003, Plant Physiol Biochem. 41: 767-72). Here, soybean cell suspension cultures were treated with various concentrations of Cd(2+) (1-10 microM) and the following enzymes were analyzed by native electrophoresis: superoxide dismutase (SOD), catalase (CAT), peroxidase (POX) and ascorbate peroxidase (APOX). We found a significant correlation between the cadmium-induced changes of soybean cell culture growth and the isoenzyme pattern of the antioxidant enzymes. The results suggest that inhibition of growth and modification of antioxidant defense reactions appear in soybean cells when Cd(2+) concentration in culture medium increases only slightly, from 4 to 6 microM.

Previously, a stable cell suspension of cucumber tolerant to 100 microM CdCl(2) was obtained (Gzyl & Gwóźdź, 2005, Plant Cell Tissue Organ Cult 80: 59-67). In this study, the relationship between the activity of antioxidant enzymes and cadmium tolerance of cucumber cells was analyzed. A cadmium-sensitive and the cadmium-tolerant cell lines were exposed to 100 microM and 200 microM CdCl(2) and the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APOX) and guaiacol peroxidase (POX) were determined. In the sensitive cell line, a decrease of total activity of SOD and POX was observed, whereas the activity of CAT and APOX significantly increased in metal-supplemented medium. By contrast, in the tolerant cells, the total activity of antioxidant enzymes decreased (SOD, CAT) or was maintained at approximately the same level (APOX, POX). Moreover, a different pattern of isoenzyme activity was observed in the tolerant and sensitive cells. These results suggest that an enhanced activity of antioxidant enzymes is not directly involved in the increased tolerance to cadmium of the selected cucumber cell line.

Abstract. Soils in Arctic regions currently enjoy attention because of their sensitivity to climate change. It is therefore important to understand the natural processes and rates of development of these soils. Specifically, there is a need to quantify the rates and interactions between various landscape-and soil-forming processes. Soil chronosequences are ideal natural experiments for this purpose. In this contribution, we combine field observations, luminescence dating and soil-landscape modelling to improve and test our understanding of Arctic soil formation. The field site is a Holocene chronosequence of gravelly raised marine terraces in central Spitsbergen.Field observations show that soil-landscape development is mainly driven by weathering, silt translocation, aeolian deposition and rill erosion. Spatial soil variation is mainly caused by soil age, morphological position within a terrace and depth under the surface. Luminescence dating confirmed existing radiocarbon dating of the terraces, which are between ∼ 1.5 and ∼ 13.3 ka old. The soil-landscape evolution model LORICA was used to test our hypothesis that the field-observed processes indeed dominate soil-landscape development. Model results additionally indicated the importance of aeolian deposition as a source of fine material in the subsoil for both sheltered and vegetated trough positions and barren ridge positions. Simulated overland erosion was negligible. Consequently, an un-simulated process must be responsible for creating the observed erosion rills. Dissolution and physical weathering both play a major role. However, using present-day soil observations, the relative contribution of physical and chemical weathering could not be disentangled. Discrepancies between field and model results indicate that soil formation is non-linear and driven by spatially and temporally varying boundary conditions which were not included in the model. To conclude, Arctic soil and landscape development appears to be more complex and less straightforward than could be reasoned from field observations.