Vol. XXVIII, No. 2 (March – April 2024)
Full issue:   EC_2_2024_eng_opt.pdf

CONTENTS

ECOLOGICAL PROBLEMS IN PERMAFROST ZONE

  • Suleymanov A.A., Aprosimov D.A., Basharin N.I., Lytkin V.M. Rural communities of the Republic of Sakha (Yakutia) under conditions of permafrost degradation (on the example of the village of Ulakhan-An)
    Abstract
    The issues of permafrost degradation and its impact on life-support system are discussed by the example of the Ulakhan-An village (Khangalassky ulus, central Yakutia). The extent and forms of manifestation of thermokarst – the main negative cryogenic process in the area – and its consequences for the local population have been studied. To achieve the goal of the research, field observations of thermokarst have been conducted, an orthophotomap of the key area has been developed, and a survey of local residents via questionnaires and narrative interviews has been performed. As a result, the extent and intensity of thermokarst development have been clarified. At present, thermokarst is mainly at its initial stage. The main consequences of permafrost degradation for the local population and key actors of agricultural activity have been determined. The Ulakhan-An residents’ perception of and adaptation to the natural challenges that have arisen are noted.
     Keywords
    Yakutia, rural livelihoods, climate change, permafrost degradation, thermokarst

PERMAFROST MICROBIOLOGY

  • Zakharyuk A.G., Trubitsyn V.E., Vishnivetskaya T.A., Rivkina E.M., Shcherbakova V.A. Microbial reduction of Fe(III) in tundra soil samples from the East Siberian Arctic
    Abstract
    Enrichment cultures of psychrophilic and psychrotolerant bacteria capable of reducing ferric iron at temperatures of 6 to 15°C were obtained from samples of two tundra soils from the Bykovsky Peninsula (Northern Yakutia, eastern sector of Russian Arctic). The highest concentrations of Fe(II) were observed in enrichment cultures grown with the use of a soluble ferric salt in the form of Fe(III) citrate. Furthermore, anaerobic communities from two enrichment cultures derived from permafrost soil samples of the Mammoth Khayata tract and cultivated at 15°C demonstrated a preference for insoluble Fe(III) oxide as an electron acceptor while utilizing acetate and formate as electron donors. Experimental data on the composition of microbial communities inhabiting permafrost soils were obtained through molecular biology and bioinformatics methods. Notably, this study presents a novel comparison between the composition of a naturally occurring microbial community that developed over an extended period under natural conditions at low temperatures, and a laboratory-cultivated microbial community. The results demonstrate that prokaryotic communities of the soils of Arctic ecosystems of Yakutia are phylogenetically diverse despite the cold and oligotrophic (nutrient-poor) conditions. While representatives of Proteobacteria and Actinobacteria phyla dominate in natural samples of tundra soil (~30–50%), the cultivated microbial community obtained in vitro from natural samples was dominated by Firmicutes (38%).
     Keywords
    tundra zone soils, Arctic, iron reduction, anaerobic communities, metagenome

PERMAFROST ENGINEERING

  • Anikin G.V., Spasennikova K.A. Cooling devices designed to restore the loading capacity of soils under existing buildings and structures
    Abstract
    A new device for temperature stabilization of frozen soils is suggested. The advantage of the proposed system is the ability to install the evaporative part of the system under the construction and operating facilities. The difference from the analogous systems is the ability to repair and replace individual evaporator pipes without dismantling the entire device while maintaining its high freezing capacity. To assess the efficiency of the proposed system, an analytical mathematical model of its functioning has been developed. The modeling of the functioning of the seasonal cooling device for the climatic conditions of the Arctic cities of Varandey, Salekhard, and Igarka has been carried out. It is shown that this device can always freeze the soil under emergency buildings and structures.
     Keywords
    permafrost, soil, seasonal cooling unit, condenser, pipeline, evaporator unit, condenser, pipeline, evaporator

SNOW COVER AND GLACIERS

  • Ivanov M.M., Gurinov A.L., Golosov V.N., Kuzmenkova N.V., Alexandrin M.Yu., Uspenskiy M.I., Shorkunov I.G., Garankina E.V. Bottom sediments as a natural record of deglaciation in the basin of lake Syltrankel, Elbrus region
    Abstract
    Deglaciation history of the Syltrankel high-mountain lake basin (Mt. Elbrus region, Northern Caucasus) from the end of the 19th to the end of the 20th centuries was reconstructed. In 2022, a comprehensive examination of the area was carried out, including sampling of the bottom sediments and their radioisotope dating, structural and textural analysis, and counting the number of varves. Simultaneously, a set of published sources; topographic maps; ground, satellite, and aerial photographs; and field observations were analyzed to determine the positions of the edges of glaciers at different times. In the formation of bottom sediments, four stages correlating with the state of mountain glaciation and changes in the configuration of the lake’s drainage area were identified. Converging results obtained on the basis of independent sources indicate the high methodological value of studying bottom sediments of mountain lakes as one of the few environmental archives that record glaciation changes in the dynamic conditions of high mountains.
     Keywords
    bottom sediments, mountain lakes, mountain glaciers, deglaciation, sediment yield, radioisotopes, varves, paleoarchives, Northern Caucasus

CLIMATE AND CRYOSPHERE

  • Fedorov V.M., Frolov D.M. Solar geochronology of the Late Pleistocene and Holocene
    Abstract
    The calculation of the Earth’s insolation with high spatial and temporal resolution made it possible to calculate solar characteristics that reflect changes in astronomical factors regulating variations in the incoming solar radiation and in the intensity of radiative heat transfer (meridional, in the ocean–continent system, and interhemispheric). In accordance with this, the astronomical theory of climate change has been modernized on the Holocene scale. Based on the synchronization of global climatic events with extremes of solar characteristics in the Holocene and Late Pleistocene, a method of solar geochronology is proposed, which makes it possible to clarify the chronology of global climatic events and explain their origin.
     Keywords
    astronomical theory of climate change, variations of insolation, radiative heat transfer, synchronization, solar geochronology, Late Pleistocene, Holocene