Polish Polar Research

This paper presents a review of geophysical studies of the crust and the lithosphere- asthenosphere boundary (LAB) in the ocean-continent transition in the area of Spitsbergen (Svalbard Archipelago) in high Arctic. Over last decades many investigations were performed during Polish geophysical expeditions, as well as in the framework of international cooperation with scientists from Germany, Japan, Norway and USA. We compiled here existing seismic, gravity and thermal models down to LAB depth along the 800 km long transect extending from the actively spreading Knipovich Ridge, across southern Spitsbergen to the Kong Karls Land Volcanic Province. The results of all methods are very consistent, although they are sensitive to different physical parameters: seismic wave velocities, densities and thermal. The thinnest lithosphere of only 12 km is found beneath the Knipovich Ridge. Only 50 km to the west and 50 km to the east of the ridge the LAB depth increases to about 30 km, and this value corresponds to the oceanic structure of the North Atlantic Ocean. Beneath southern Spitsbergen the LAB depth is about 55 km and increases to 90–100 km beneath continental structure of the Barents Sea. The uplift of the LAB close to distance of 700 km along transect could be correlated with Kong Karls Land Volcanic Province.

Independent Arctic records of temperature and precipitation from the same proxy archives are rare. Nevertheless, they are important for providing detailed information on long-term climate changes and temperature-precipitation relationships in the context of large-scale atmospheric dynamics. Here, we used chironomid and cladoceran fossil assemblages to reconstruct summer air- temperature and water-level changes, during the past 400 years, in a small lake located in Finnish Lapland. Temperatures remained persistently cold over the Little Ice Age (LIA), but increased in the 20th century. After a cooler phase in the 1970s, the climate rapidly warmed to the record-high temperatures of the most recent decades. The lake-level reconstruction suggested persistently wet conditions for the LIA, followed by a dry period between ~1910 and 1970 CE, when the lake apparently became almost dry. Since the 1980s, the lake level has returned to a similar position as during the LIA. The temperature development was consistent with earlier records, but a significant local feature was found in the lake-level reconstruction – the LIA appears to have been continuously wet, without the generally depicted dry phase during the 18th and 19th centuries. Therefore, the results suggest local precipitation patterns and enforce the concept of spatially divergent LIA conditions.

Aeolian activity is common on ice free areas in regions with permafrost occurrence. Sparse high-Arctic tundra vegetation, modifying surface air flow and sediments transport, influences the generation of individual landforms and their assemblages. Observations were carried in central Spitsbergen (Svalbard), characterized by quasi-continental polar climate conditions with dry summers and common existence of winds velocities above loamy-sandy sediments transportation threshold. Dryas aeolian landforms created from aeolian material trapped by Dryas octopetala dwarf shrub were diagnosed. Main morphogenetic plants are accompanied by Saxifraga oppositifolia and Bistorta vivipara, rounded out with biological soil crust. Small size of semi-circular and semi-elliptic forms (0.25–0.85 m2) is related to low type of D. octopetala slowly growing on raised marine terraces. Aeolian sediments are characterised by low level of organic matter content. They exhibit diversified mineralogical composition resulting from variable petrography of source glacial and fluvioglacial covers. Eightpetal mountain avens are a dendroflora species composing phytocoenoses of plant communities related to the end stages of biocoenotic succession. Presented data indicate the reference environmental state for any research on plant cover response in the environment of aeolian activity during climate change.

Thirty-one tidewater glacier bays in Spitsbergen Island were visited by yachts in August 2011, 2015, 2016 and 2017. Surface water samples were taken by volunteers, the members of the yacht crews, to measure concentrations of suspended matter, salinity, and temperature. Secchi disc measurements were used to measure water transparency. A series of photographs along the glacier fronts were taken and used to count seabirds that were present near the glacier cliff. Basic topographic features (depth, presence of a sill, exposure, glacier width) were obtained from sea charts and analysed. The number of preying Black-legged Kittiwakes (Rissa tridactyla; a target species) ranged from zero to over 2000 birds during 89 visits. High concentrations of individuals (above 100) were observed in 20% of the visits, while no birds were recorded in 42% of the visits. There was no statistical correlation between the topographic features of the glacier and bird concentrations. To our present knowledge, Black-legged Kittiwake feeding spots are random and temporary in time in which (or soon after) the juveniles are leaving the colony. They are a recurrent phenomenon related to krill abundance and simultaneous jet-like meltwater discharges.

Here we investigate the microbiomes of the soil samples from the Yamal Peninsula (the surroundings of Salekhard city, Russian Federation) using a high-throughput sequencing approach. The main goal was to investigate the impact of mining on soils within the following regeneration, both during the reclamation practice and natural self-growth. Several quarries were studied, engaged in sand, clay and chromatic ores mining. The taxonomic analysis of the soil microbiomes revealed 50 bacterial and archaeal phyla; among the dominant phyla were: Proteobacteria, Actinobacteria, Acidobacteria, Chroloflexi, Gemmatimonadetes, Verrucomicrobia, Planctomycetes, Bacteroidetes, AD3, and Nitrospirae. Compared to the typical tundra soil, which was chosen as a control, the disturbed soils had increased biodiversity and total counts for soil bacteria, archaea, and fungi, especially in the cryosolic horizon. The different mining strategies caused significantly different transformations of soil microbiomes, which was less pronounced for self-growth compared to reclaimed quarries. This isolation of the reclaimed quarry was mainly associated with the increase of the amount of acidobacteria (fam. Koribacteraceae and Acidobacteriaceae and order Ellin6513), some proteobacterial taxa (fam. Syntrophobacteraceae), and Chloroflexi (fam. Thermogemmatisporaceae). The study also revealed bacteria, which tend to be specific for marine tundra environments: gemmatimonadetes from the order N1423WL and Chloroflexi bacteria from the order Gitt-GS-136.