Sverdrup Research Station, Ny-Ålesund: projects/activities

Effects of UV-B radiation on microbial communities in Kongsfjorden in relation to metal and dissolved organic matter availabillity.

As a result of the increasing atmospheric CO2 levels and other greenhose gases due to anthropogenic activities, global and water temperature is rising. The objectives of our project might be summarized as follows: I. To measure the activity of the enzymatic systems involved in carbon, nitrogen and phosphorus uptake (carbonic anhydrase, nitrate reductase and alkaline phosphatase) in selected macroalgae. To assess the optimal concentration of inorganic nitrogen and phosphorus for growth and photosynthesis. To study the total concentration of carbon and nitrogen metabolites in the macroalgae (proteins, total carbohydrates, and lipids) in order to define the possible existence of nutrient limitation. II. To simulate the conditions of climate change, represented as CO2 enrichment and increasing UV radiation, on the activity of carbon, nitrogen and phosphorus uptake mechanisms. III. To screen the activity of the enzymatic systems previously detailed in macroalgae from the Konjsfjord, in order to know their nutritional state.

Changes in surface reflection at the arctic tundra at Ny-Ålesund, Svalbard (79 N) were monitored during the melting season 2002 using a low cost multispectral digital camera with spectral channels similar to channels 2, 3, and 4 of the Landsat Thematic Mapper satellite sensor. The camera was placed 474 m above sea level at the Zeppelin Mountain Research Station and was programmed to take an image automatically every day at solar noon. To achieve areal consistency in the images (which is necessary for mapping purposes) the images were geometrically rectified into multispectral digital orthophotos. In contrast to satellite images with high spatial resolution the orthophotos provide data with high spatial and high temporal resolution at low cost. The study area covers approximately 2 km2 and when free of snow, it mainly consists of typical high arctic tundra with patchy vegetation and bare soil in between. The spectral information in the images was used to divide the rectified images into maps representing different surface classes (including three subclasses of snow). By combining classified image data and ground measurements of surface reflectance, a model to produce daily maps of surface albedo was developed. The model takes into account that snow-albedo decreases as the snow pack ages; and that the albedo decreases very rapidly when the snow pack is shallow enough (20-30 cm) to let surface reflectance get influenced by the underlying ground. Maps representing days with no image data (due to bad weather conditions) were derived using interpolation between pixels with equal geographical coordinates. The time series of modeled albedo-maps shows that the time it takes for the albedo to get from 80% to bare ground levels varies from less than 10 days in areas near the coast or in the Ny-Ålesund settlement till more than 70 days in areas with large snow accumulations. For the entire study area the mean length of the 2002 melting period was 28.3 days with a standard deviation of 15.1 days. Finally, the duration of the snowmelt season at a location where it is measured routinely, was calculated to 23 days, which is very close to what is the average for the last two decades.

To investigate arctic foxes physiological adaptations to life at high latitudes. Resting and running metabolic rates, body weight, food intake, body core temperature, heart rate, and blood parameters were examined during different seasons and during periods of food deprivation.

The structure and role of the cyanobacterial communities that colonise bare soils and fix nitrogen in the arctic ecosystem will be studied. The planned activities will focus on the isolation, identification and characterisation of cyanobacteria from arctic habitats and on the changes of the cyanobacterial community along a transect from a retreating glacier front to a more stable habitat characterised by the presence of mature vegetation. For these purposes, a polyphasic approach encompassing microbiological, morphological and molecular techniques will be applied to environmental samples and isolated cultures. The obtained results will give new insights on the diversity and role of nitrogen fixing cyanobacteria in the arctic and, in more general terms, on ecosystem development under changing climatic conditions.

To evaluate temporal variation in arctic fox numbers and their food resourses in the Kongsfjorden area. The number of foxes captured per 100 trap-days are used as an index of fox density termed "Fox Capture Index". The observations of denning activity i.e. observation of number of arctic fox litters and litter size at den are termed "Fox Den Index" as a second index of fox abundance. A third index is termed "Fox Observation Index". This index is based on both observations of adult foxes seen away from breeding dens pr 100 h field work and reports on request from scientists and local people on observations of adult foxes during summer. In addition, reports on observation of fox tracks in the study area were collected in 1990-2001 as a fourth index, which were called "Fox Track Index". The field census are conducted for 10 days starting at the end of June. All dead foxes in the area should be collected.