Cyanobacterial Diversity of the Northern Polar Ural Mountains

This study provides new results from an inventory of cyanobacterial species from the Northern Polar Ural Mountains. The article also compiles all existing published data on the cyanobacterial diversity of the region. This ecoregion is located in a unique geographical position in the transition between the sub-Arctic and low Arctic zones and heterogeneous natural conditions. Likely, the unexplored biodiversity of this area’s terrestrial cyanobacteria is high. In total, 52 localities were studied, with 232 samples collected. Cyanobacterial samples were studied under a light microscope. Species were identified based on morphological characteristics only. A total of 93 species of cyanobacteria were identified in different habitats; 70 species were found on wet rocks, 35 on the shores of water bodies, 27 in slow streams, and 21 on waterfalls. In total, 37 species are reported as part of the Ural flora for the first time, while three species (Chroococcus ercegovicii, Gloeocapsopsis cyanea, Gloeothece tepidariorum) were detected in Russian territory for the first time. The composition of the cyanobacterial flora of the Polar Urals was compared with the flora of the nearby Arctic and sub-Arctic regions. According to the Sorensen similarity index, the Polar Urals’ flora is more like the flora of Nenets Autonomous Okrug.

Northern distribution limits of Sphagnum wulfianum (Sphagnaceae, Bryophyta) in the Northern Palearctic – records from tundra: coincidence or rule?

Sphagnum wulfianum is a widespread circumboreal species in the Northern Hemisphere. The distribution of this species in the Northern Palearctic was studied by generalizing and combining data from open sources (GBIF, literature data) and herbarium samples from LE, MW, NSK, and MHA into a single database. Data from herbarium labels and annotated lists were put on the map of Eurasia as points in the ArcGis 10.0 software. Analysis of the data shows that out of 3061 points 15 samples only were found in the tundra zone, which is 0.49% of all samples. This demonstrates that tundra habitats are not typical for S. wulfianum. Spatial analysis of samples collected in the Arctic of Eurasia shows that S. wulfianum was found only in the tundra of Yamal, Taz, and Taimyr peninsulas and in the part of Bolshezemelskaya tundra, which is adjacent to the Polar Urals. Analysis of vegetation history shows that S. wulfianum is a relic of the Holocene climatic optimum, preserved in the present southern tundra since the existence of forest vegetation. It is unknown from the tundras of Yakutia and Chukotka and from the mountainous tundras of Scandinavia, where any forest vegetation is unknown in the Holocene.

Spatiotemporal dynamics of encroaching tall vegetation in timberline ecotone of the Polar Urals region, Russia

Previous studies discovered a spatially heterogeneous expansion of Siberian larch into the tundra of the Polar Urals (Russia). This study reveals that the spatial pattern of encroachment of tree stands is related to environmental factors including topography and snow cover. Structural and allometric characteristics of trees, along with terrain elevation and snow depth were collected along a transect 860 m long and 80 m wide. Terrain curvature indices, as representative properties, were derived across a range of scales in order to characterize microtopography. A density-based clustering method was used here to analyze the spatial and temporal patterns of tree stems distribution. Results of the topographic analysis suggest that trees tend to cluster in areas with convex surface. The clustering analysis also indicates that the patterns of tree locations are linked to snow distribution. Records from the earliest campaign in 1960 show that trees lived mainly at the middle and bottom of the transect across the areas of high snow depth. As trees expanded uphill with a warming climate in recent decades, the high snow depth areas also shifted upward creating favorable conditions for recent trees growth at locations that were previously covered with heavy snow. The identified landscape signatures of increasing above-ground Arctic biomass in terms of tall vegetation can facilitate scaling to larger area regions.

U-Th-He Geochronology of Pyrite from Alteration of the Au-Fe-Skarn Novogodnee-Monto Deposit (Polar Urals, Russia)—The Next Step in the Development of a New Approach for Direct Dating of Ore-Forming Processes

We report on the application of the U-Th-He method for the direct dating of pyrite from the alteration halo of the Novogodnee-Monto Au-Fe-skarn deposit, Polar Urals. The deposit is genetically related to the formation of volcanogenic complexes of the Ural Paleozoic belt. A modification of the original methodology for measuring U, Th and He isotopes in a single grain allowed us to determine a U-Th-He age of 382 ± 8 Ma (2σ) based on six pyrite samples from the altered rocks of the deposit (U mass fraction ~0.2 mg/kg; Th/U ~ 3.5; 4He specific volume ~ 10−5 cm3·STP·g−1). This age is consistent with estimates of the age of ore formation and coeval with the end of the period of island arc magmatic activity. Our results indicate that U-Th-He dating for pyrite samples of ~1 mg in weight from the hydrothermal-metasomatic halo of ore bodies is possible, providing a crucial next step in the development of U-Th-He pyrite geochronology.

Uphill Shifts of Fungal Fruiting Due to Climate Change at the Polar Urals

Due to the ongoing climatic changes in the Arctic, the ranges of many plants and animal species are rising higher into the mountains, into the treeline; however, such studies are rare for fungi. The 60-year fruiting dynamics of 66 species of Agaricomycetous macrofungi has been studied along the altitudinal transect located on the slope of Slantsevaya Mountain (Polar Urals, Russia). It has been found that the three basic trophic groups (mycorrhizal, saprobes on litter and soil, and saprobes on wood) fruit higher in the mountains. Additionally, for most of the studied species, a tendency towards upward displacement of fruiting was revealed. The rise in fruiting for saprobes on litter and soil was the most obvious. Mycorrhizal fungi associated with woody plants showed the least uplifting effect. Fungal species that were characterized by fruiting higher up the mountainside half a century ago show stronger upward shifts compared to species previously bearing fruit only at the mountain foot. Probably, such a reaction of the aboveground mycobiota is similar to the processes occurring in the soil, which are associated with an active increase in the decomposition rate of the litter, an increase in the depth of permafrost thawing, and a significant redistribution of the soil water balance. On the other hand, the rise of fungi is associated with an increase of plant biomass in the middle and upper parts, which are the most important sources of fungal nutrition.