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A rare phenomenon—the long-range atmospheric transport of dust from the arid and semiarid territories of the Caspian Sea region through the center of the European part of Russia to its Arctic areas—was recorded in December 2023 during a field study of the physicochemical characteristics of airborne particles in Moscow and the snow composition in Arkhangelsk oblast. The analysis of the trajectories of the air mass transport, dynamics of spatial and temporal variability of the mass concentration of PM2.5 and PM10 matter in Moscow oblast, and numerical estimates and spatial distributions of near-surface concentrations and optical characteristics of airborne particles in the European part of Russia (according to the MERRA-2 reanalysis estimates) confirmed an increase in aerosol air pollution in the territories from the Caspian Sea to Arkhangelsk oblast. The snow sample taken in the area of Pinega Nature Reserve, Arkhangelsk oblast, in the spring of 2024, in the snow cover at a height of 18–20 cm (with a total snow thickness of 65 cm), was found to contain a yellowish layer of snow that fell in December 2023. The preliminary studies of the sample from this snow showed the presence of a large amount of organic suspended matter and plant residue, which in winter indicates transport of atmospheric aerosol from the southern regions of Russia. [ABSTRACT FROM AUTHOR]

Materials determining the possible pathways of Arctic zone colonization by representatives of thermophilic ichthyofauna are presented. The previously proposed hypothesis that the fish of the thermophilic complex that lived in the White Sea basin during the Subboreal period (sterlet, blue bream, common rudd, white-eye bream, and asp) and were considered extinct during the subsequent cooling in the Subatlantic period, adapted to changed conditions, stayed in particular areas of their range, and became part of the modern ichthyofauna in limited numbers have been elaborated and confirmed. The possible pathways of spontaneous introduction of the Caspian thermophilic species, white-eye bream, and asp to the Northern Dvina basin are considered. Populations of rudd and blue bream, rare thermophilic species for the region, have been detected and studied in the lakes of the Kenozersky National Park. Rudd, a relict species of the Holocene thermal maximum, was previously recorded only in several floodplain lakes of the middle reaches of the Northern Dvina River. The Kenozero population of rudd is the first case of finding epresentatives of this species in the Onega River basin. Blue bream can be also considered a relict found in the territory of the region only in one lake system of the Kenozersky National Park and several small lakes of the Siysky State Nature Reserve. [ABSTRACT FROM AUTHOR]

The article considers a procedure for constructing river valleys of lowland subarctic territories based on a digital elevation model in SAGA GIS software applied to the case of Arkhangelsk oblast. Two algorithms for calculating drainage areas (D8 and MFD) are analyzed, and their advantages and drawbacks in digital modeling of an MFD river network are demonstrated. [ABSTRACT FROM AUTHOR]

The article provides an overview of literary and archival materials on the historical geography of pearl fishing, as well as a list of rivers of the Southern White Sea Region, where in the 17th-20th centuries pearls were mined. The most significant resources of pearls have been concentrated in the rivers Solza (with the tributary Kazanka) and Kozha (with the tributary Syvtuga) where there was regular and profitable trade of pearls for a long time. At present, pearl mussel populations have been preserved in these rivers, sometimes with a fairly high density. The volumes and frequency of pearl fishing can be indicators of shellfish abundance. [ABSTRACT FROM AUTHOR]

Water bodies in the city of Mirny (Arkhangelsk oblast, Russia) and its environs are the northernmost sites where the introduced Chinese sleeper is registered. The first data on the Chinese sleeper parasite fauna in this region are obtained; Trichodina mutabilis, Goussia sp., Spironucleus sp., and larvae of Nematoda gen. sp. are found. [ABSTRACT FROM AUTHOR]