Lena River Research Articles

ЛЕНСКИЕ ТРОВАНТЫ: ГИПОТЕЗА И МОДЕЛЬ ОБРАЗОВАНИЯ

Unusual nodule formations have long been known in the steep banks of the Lena River and its tributaries. Their belonging to the category of Trovants (trovantogenesis) has been established. It is shown that trovants formation (trovantogenesis) is a process of specific transformation of cemented sands to varying degrees in platform and sub-platform environments. The hypothesis expressed by Romanian geologists about the pseudo-concretionary nature of the trovants has been confirmed. The aqua-dissipative model of their genesis is proposed. The variant of genetic сlassification of small geological bodies wherein trovants are classified as a consistent type is discussed.

ПОЛИПЛОИДИЯ У ВОДНЫХ И ПРИБРЕЖНО-ВОДНЫХ СОСУДИСТЫХ РАСТЕНИЙ СЕВЕРО-ВОСТОКА АЗИИ

The chromosome numbers of aquatic and semiaquatic vascular plants growing in extreme North-East Asia, east of the Lena River, were analyzed. We have reviewed the information about the karyological peculiarity of the aquatic flora based on published data, including our own definitions. The karyological data are considered depending on the taxonomic position, distribution and ecological characteristics of the species. The chromosome numbers are known for 119 out of 123 species. There is no data on Zannichellia komarovii, Eleocharis termale, Stuckenia subretusa and Potamogeton sibiricus. In the aquatic flora of North-East Asia, the proportion of polyploids is higher (79%) than that reported for the entire Beringian flora (69%). We analyzed species for the presence of polyploidy depending on the type of area. Analysis by latitudinal groups revealed that all Arctic and hypoarctic species of aquatic plants are polyploids. The minimum proportion of polyploids is observed among arctoboreal species. Analysis by longitudinal groups revealed that the lowest proportion of polyploids was noted among species found only in Eurasia and absent in North America (61%), and it was the highest among pluriregional species (96%). The species of the families Cyperaceae, Lemnaceae, Ranunculaceae and Poaceae are characterized by a high level of variability in the number of chromosomes. The greatest variety of chromosome numbers is observed in the polymorphic species Caltha palustris s. l., Agrostis stolonifera, Dupontia fisheri s. l., Phragmites australis, in all species of the genus Eleocharis, and in Nymphaea tetragona, Acorus calamus, Calla palustris. The isolated cases of a high level of ploidy were found in the extreme northeast, at the northern borders of ranges, in 3 species - Hippuris vulgaris, Arctophila fulva and Beckmannia syzigachne. Only diploids are known in the families Equisetaceae, Typhaceae, Zosteraceae from the flora of North East Asia. We revealed the existence of several chromosomal races in Ranunculus gmelinii and Caltha palustris (Ranunculaceae) in the Magadan region; the distribution of chromosomal races is partly related to geographic location and partly to plant habitats. Rare karyotypes in these species are observed in aquatic forms with mainly vegetative reproduction, growing in non-freezing watercourses.

Monitoring the Spring Flood in Lena Delta with Hydrodynamic Modeling Based on SAR Satellite Products

Due to the remote location and the extreme climate, monitoring stations in Arctic rivers such as Lena in Siberia have been decreasing through time. Every year, after a long harsh winter, the accumulated snow on the Lena watershed melts, leading to the major annual spring flood event causing heavy transport of sediments, organic carbon, and trace metals, both into as well as within the delta. This study aims to analyze the hydrodynamic processes of the spring flood taking place every year in the Lena Delta. Thus, a combination of remote sensing techniques and hydrodynamic modeling methodologies is used to overcome limitations caused by missing ground-truth data. As a test site for this feasibility study, the outlet of the Lena River to its delta was selected. Lena Delta is an extensive wetland spanning from northeast Siberia into the Arctic Ocean. Spaceborne Synthetic Aperture Radar (SAR) data of the TerraSAR-X/TanDEM-X satellite mission served as input for the hydrodynamic modeling software HEC-RAS. The model resulted in inundation areas, flood depths, and flow velocities. The model accuracy assessed by comparing the multi-temporal modeled inundation areas with the satellite-derived inundation areas ranged between 65 and 95%, with kappa coefficients ranging between 0.78 and 0.97, showing moderate to almost perfect levels of agreement between the two inundation boundaries. Modeling results of high flow discharges show a better agreement with the satellite-derived inundation areas compared to that of lower flow discharges. Overall, the remote-sensing-based hydrodynamic modeling succeeded in indicating the increase and decrease in the inundation areas, flood depths, and flow velocities during the annual flood events.

Land reservation for the construction of a bridge over the Lena River of the Republic of Sakha (Yakutia)

Land reservation for the construction of a bridge over the Lena River of the Republic of Sakha (Yakutia)

Spatial patterns and distributional controls of total and methylated mercury off the Lena River in the Laptev Sea sediments

A warmer climate is predicted to accelerate the export of mercury (Hg) from Siberian rivers to the Arctic Ocean, yet there is a dearth of process-oriented studies on the speciation and fate of Hg in the shelf sea system. Here, we present data on total Hg (HgT) and methylmercury (MeHg) in Laptev Sea surface sediments along a cross-shelf transect starting at the mouth of the Lena River. Concentrations of HgT along the 330 km cross-shelf transect ranged within a fairly narrow span from 480 to 150 pmol g−1 d.w., while concentrations of MeHg decreased one hundredfold from 13 pmol g−1 d.w. near the Lena river to 0.095 pmol g−1 d.w. in the more distall stations. The highest concentrations of HgT and MeHg were observed close to the river delta and were associated with a high supply of organic carbon (OC). Enrichment of the OC normalized HgT concentration (HgTOC) and depletion of the OC normalized MeHg concentration (MeHgOC) across the shelf suggests bulk OC content to not be the only driver of the HgT and MeHg spatial distributions. Based on correlations observed between HgTOC and MeHgOC and proxies for sediment physics and organic matter pools we suggest the spatial distribution of Hg and MeHg to also be influenced by hydrodynamic sorting of riverine-derived material. For MeHg, depletion of the MeHgOC across the shelf is likely driven by the trapping of terrestrial MeHg in sediments close to the river delta before it is degraded in the water column.

Long-Term Variability in Ground Thermal State in Central Yakutia’s Tuymaada Valley

This paper presents the results of long-term temperature monitoring at the Yakutsk and Zeleny Lug stations, which are experimental sites, for the thermal state of valley permafrost landscapes under the conditions of modern climate warming. An analysis of the long-term data from meteorological stations in the region clearly showed one of the highest trends of increase in the mean annual air temperature in the north of Russia. Here, we established quantitative regularities in the long-term variability of the ground temperature at the bottom of the active layer and at zero amplitude. The dynamics of the ground temperature of the layer of zero amplitude during climate warming indicate the thermal stability of permafrost. The main regulating factor of the thermal state of grounds in permafrost landscapes is short-term fluctuations in the regime of snow accumulation. Active layer thickness is characterized by low interannual variability, weak climate warming responses, and insignificant trends. The results of studies of the thermal regime of soils can be extended to the same types of valley landscapes in the Lena River, and are a reliable basis for predicting heat transfer in natural and disturbed landscapes.

Evidence of dispersal between the Yenisei and the Lena river basins during the late Pleistocene within the whitefish (Coregonus lavaretus pidschian) complex

The Coregonus lavaretus (Linnaeus, 1758) complex is a morphologically and genetically diverse group of whitefish. Its taxonomic structure has been controversial for almost a century. At least 25 forms of C. lavaretus have been described in Siberia, but there is still no consensus on their intraspecific structure and taxonomy. Coregonus lavaretus pidschian (Gmelin, 1789) was described as a subspecies of C. lavaretus. Recently, it was assumed that this subspecies is also a complex. The purpose of this study was to compare the distributions of pidschian-like whitefish haplotypes in two basins of large Siberian rivers, Yenisei and Lena, and to assess the gene flow between basins of these rivers, which were connected after the last glaciation. The sequence of the following mitochondrial DNA genes, 16S rRNA (partial), tRNA-Leu (full), NADH dehydrogenase subunit 1 (full), tRNA-Ile (full), and tRNA-Gln (partial), were used for the inference of intraspecific genetic structure of C. l. pidschian. Whitefish haplotypes were clustered into two groups according to their distribution between two large Siberian river basins; however, there were shared haplotypes indicating events of migration and hybridization, which could occur when Bolshoi Yenisei and Lena river systems were connected after the last glaciation (the Late Pleistocene).

Intraspecific structure of the Coregonus lavaretus complex in water bodies of Siberia: a case of postglacial allopatric origin of Yukagirian whitefish

The results of morphological and genetic analyses of forms/species of the Coregonus lavaretus pidschian (Gmelin, 1789) complex from the Indigirka and Kolyma river basins are presented in the context of there being recent postglacial speciation events. It has been found that the studied whitefishes belong to the sparsely rakered and low lateral-line forms and have previously been described as Coregonus lavaretus pidschian n. jucagiricus Drjagin (Berg), 1932. Based on these characters, this whitefish does not differ from most Arctic whitefish populations (in particular from Coregonus lavaretus glacialis Kirillov, 1972). Analysis of variability of the ND1 gene (mtDNA) showed that whitefishes from the Indigirka and Kolyma basins belong to a distant phylogenetic lineage, which is significantly different from all previously studied whitefish lineages from the Ob, Yenisei, Lena, Anadyr, and Amur river basins. Analysis of variability of the ITS1 fragment (nDNA) showed that all studied forms/species (from Ob River to Amur River basins), including C. l. pidschian n. jucagiricus, have a tandem arrangement of two identical nucleotide fragments and very similar nucleotide composition of the ITS1 region. Based on contemporary data, this phylogenetic lineage of the C. pidschian complex could be considered a young postglacial allopatric species.

Features of Seasonal Sea Level Oscillations in the Russian Arctic Seas

Based on the analysis of long series of monthly mean sea level values from the database of the PSMSL and ESIMO portals, we obtained estimates of the mean and extreme amplitudes of seasonal oscillations. The mean amplitude of annual sea level oscillations in the White Sea is 7 cm, in the Barents Sea is 9–10 cm, in the Kara Sea, is 8–9 cm, in the Laptev Sea, is 10–11 cm, in the East Siberian and Chukchi seas is 13–14 cm. In the estuarine areas of seas, the amplitude of annual oscillations increases, and the semiannual, third-annual, and quarter-annual components appear in the sea level spectra. They are formed due to the asymmetry of the seasonal sea level variation with a sharp maximum during the flood period in June. Interannual changes in the amplitude of seasonal oscillations were identified and estimates of their extreme values were obtained. In some years, the amplitude of seasonal oscillations reaches 50 cm in the Yenisei Gulf and Gulf of Ob, 60 cm near the mouth of the Lena River, and 75 cm at the mouth of the Olenek River.

Structure and Variability of the Lena River Plume in the South-Eastern Part of the Laptev Sea

Structure and Variability of the Lena River Plume in the South-Eastern Part of the Laptev Sea

Brachiopods of the Carboniferous-Permian Boundary Deposits of the Kubalakh Section (Lower Reaches of the Lena River, Northern Verkhoyanie)

The paper presents new data on the vertical distribution of brachiopods in the Carboniferous-Permian boundary deposits (the Kubalakh Formation) of the Kubalakh section (lower reaches of the Lena River). The deposits of the Kubalakh Formation are divided by the valley of the Kubalakh Creek into two outcrops, which are suggested to be considered as subformations. A brachiopod complex Jakutoproductus protoverkhoyanicus Kaschirzew, Verchojania abramovi Makoshin, Verchojania cf. monstrosus (Ganelin), Verchojania sp., Cancrinella? alazeica Zavodowsky, Tornquistia kolymensis Afanasjeva, Tornquistia sp., Rhynoleichus sp., Rhynchopora sp., characteristic of the Jakutoproductus protoverkhoyanicus Zone of the Kygyltasian Horizon of the Verkhoyanie is recognized in the Lower Kubalakh Subformation. A brachiopod complex Jakutoproductus verkhoyanicus (Fredericks), Jakutoproductus crassus Kaschirzew, Waagenoconcha aff. wimani (Fredericks), Orbiculoidea sp., Rhynchopora sp., characteristic of the Jakutoproductus verkhoyanicus Zone of the Khorokytian Horizon of the Verkhoyanie is recognized in the Upper Kubalakh Subformation. Based on the data presented, the Carboniferous-Permian boundary should be drawn within the Kubalakh Formation, rather than at the base of the Tuora-Sis formation, as is was accepted on the basis of the latest Unified Regional Scheme of Permian Deposits in the Verkhoyansk-Okhotsk region.

The Rock Magnetic Portrait of the Devonian Section of Stolb Island (Lena River Delta)

The Rock Magnetic Portrait of the Devonian Section of Stolb Island (Lena River Delta)

Meat Quality Assessment of Lake Minnow Phoxinus percnurus (Pallas) of the Lena River Basin

Meat Quality Assessment of Lake Minnow Phoxinus percnurus (Pallas) of the Lena River Basin

Developing and Testing a Deep Learning Approach for Mapping Retrogressive Thaw Slumps

In a warming Arctic, permafrost-related disturbances, such as retrogressive thaw slumps (RTS), are becoming more abundant and dynamic, with serious implications for permafrost stability and bio-geochemical cycles on local to regional scales. Despite recent advances in the field of earth observation, many of these have remained undetected as RTS are highly dynamic, small, and scattered across the remote permafrost region. Here, we assessed the potential strengths and limitations of using deep learning for the automatic segmentation of RTS using PlanetScope satellite imagery, ArcticDEM and auxiliary datasets. We analyzed the transferability and potential for pan-Arctic upscaling and regional cross-validation, with independent training and validation regions, in six different thaw slump-affected regions in Canada and Russia. We further tested state-of-the-art model architectures (UNet, UNet++, DeepLabv3) and encoder networks to find optimal model configurations for potential upscaling to continental scales. The best deep learning models achieved mixed results from good to very good agreement in four of the six regions (maxIoU: 0.39 to 0.58; Lena River, Horton Delta, Herschel Island, Kolguev Island), while they failed in two regions (Banks Island, Tuktoyaktuk). Of the tested architectures, UNet++ performed the best. The large variance in regional performance highlights the requirement for a sufficient quantity, quality and spatial variability in the training data used for segmenting RTS across diverse permafrost landscapes, in varying environmental conditions. With our highly automated and configurable workflow, we see great potential for the transfer to active RTS clusters (e.g., Peel Plateau) and upscaling to much larger regions.

Interannual Variability of the Lena River Plume Propagation in 1993–2020 during the Ice-Free Period on the Base of Satellite Salinity, Temperature, and Altimetry Measurements

The Lena River plume significantly affects the thermohaline, optical and chemical properties of the eastern Arctic seas. We use sea surface salinity (SSS), temperature (SST), and altimetry measurements to study features of the Lena plume propagation during 1993–2020. A comparison of Soil Moisture Active Passive (SMAP) SSS measurements with in situ data obtained using the flow-through system in oceanographic surveys in 2018–2019 demonstrates good coincidence with correlation ~ 0.96 and RMSD ~ 1 psu. The SMAP data were used to reconstruct the plume evolution in 2015–2020 and to identify three main types of Lena plume propagation, which are mainly related to the variability of dominant zonal wind direction: «northern»—the plume moves to the north from the delta up to 78° N; «eastern»—the plume moves eastward along the Siberian coast up to 180° E; «mixed» between two main types. Brackish plume waters were characterized by increased temperature and sea level, which provides the opportunity for studying the Lena plume dynamics using satellite altimetry and infrared measurements. These data were analyzed to study the interannual variability of plume propagation during the ice-free period of 1993–2020. The obtained results show that the «northern» type is observed twice more often than the «eastern» one, but the «eastern» type has intensified since 2010.

The principles of compiling and the content of the Geocryological Map in the area of the bridge crossing over the Lena River

For the safe construction and operation of a bridge it is necessary to have a clear understanding of the landscape, geocryological and hydrogeological features of the territory. In this regard, a review of the geocryological study of the permafrost zone of the bridge crossing area has been prepared; the analysis of the published and archive literature on the geological structure and hydrogeological conditions of the area under study was carried out; field and fund data and data of engineering and geological surveys were studied and analyzed; control and linking field routes and geothermal measurements in wells were carried out. The results obtained in the course of this work served as the basis for the compilation of a permafrost landscape map and then a geocryological map of the bridge over the Lena river in the area of Yakutsk on a scale of 1 : 5 000. The geocryological map shows the spatial heterogeneity of the permafrost-landscape conditions of the territory under consideration due to zonal (altitudinal-belt), regional and local factors. The information base of geocryological characteristics was the data of engineering and geological surveys.

Streamflow Changes of Small and Large Rivers in the Aldan River Basin, Eastern Siberia

The flow of large northern rivers has increased, but regional patterns of changes are not well understood. The aim of this study is the estimation of monthly discharge changes of the 11 river catchments in the Aldan River basin in Eastern Siberia, the largest Lena River tributary and the sixth largest river in Russia. We considered the trend dependence on month, number of years in the sample, finish and start years, and basin area. The median fraction of samples with no trend, positive and negative trends are 70.5%, 28.5%, and 1%, respectively. Longer samples tend to show more positive trends than shorter ones. There is an increasing fraction of samples with positive trends as a function of later sample end year, whereas the start year does not result in a similar pattern. The larger basins, with one exception, have more positive trends than smaller ones. The trends in monthly streamflow have prominent seasonality with absence of positive trends in June and increasing fraction of samples with positive trends from October till April. The study reports the recent streamflow changes on the rarely analyzed rivers in Eastern Siberia, where air temperature rises faster than in average on the globe. The study results are important for water resources management in the region and better understanding of current environmental changes.

Lateglacial–Holocene environments and human occupation in the Upper Lena region of Eastern Siberia derived from sedimentary and zooarchaeological data from Lake Ochaul

In the current study, different geochemical and biological proxies, including pollen, non-pollen palynomorphs, ostracods and molluscs, from an AMS radiocarbon-dated sediment core from Lake Ochaul (54°14′N, 106°28′E; 641 m a.s.l.) are presented and discussed. Ochaul is a fresh-water lake and an archaeological site situated ca. 100 km northwest of Lake Baikal in the upper reaches of the Lena River. The 260-cm-long sedimentary record presented here spans the Lateglacial–Holocene interval, between ca. 13,500 cal yr BP and the present. The reconstructions of the postglacial vegetation and lake system development are discussed along with the regional climate dynamics and the hemispheric-scale environmental changes. During the Allerød interstadial the region around Lake Ochaul was dominated by sparse taiga forests. Cooling during the Younger Dryas led to a more open tundra landscape where trees formed patchy forest stands in climatically favourable environments. This facilitated a rapid spread of forests at the onset of the Early Holocene during which the study region was probably characterized by seasonally dry climate controlled by the interplay of higher insolation, lower global sea levels and remaining ice sheets in the North Atlantic region. After thermal and moisture optimum conditions and a maximum spread of forests during the Middle Holocene, continuous cooling and a trend to more open forests landscapes marked the Late Holocene. These long-term trends were interrupted by several relatively short episodes of change in the vegetation and algal records, which coincide with short-term (centennial-scale) Northern Hemisphere cooling/drying phases. This shows that the regional vegetation reacted sensitively to these climate oscillations. Six AMS radiocarbon dates of bone material of large herbivorous animals from the Ochaul archaeological site located at the northern shore of the lake provide important information about prehistoric hunter-gatherers and indicate that activities at the site took place at ca. 27,780–27,160 cal yr BP (95% probability range) as well as during the Mesolithic (ca. 8850–8450 cal yr BP), Early, Middle and Late Neolithic (between ca. 6840 and 5490 cal yr BP) and the Iron Age (ca. 2120–1930 cal yr BP). Our results demonstrate that despite major environmental transformations following the Last Glacial Maximum, Lake Ochaul and the Malaya Anga River valley remained attractive for large herbivores and for prehistoric hunter-gatherers, even during the Middle Neolithic cultural “hiatus” (ca. 6660–6060 cal yr BP) in Cis-Baikal, as documented by the published archaeological records.

Dynamics of Dissolved Carbon in the Mainstem of the Lena River in July 2017

Dynamics of Dissolved Carbon in the Mainstem of the Lena River in July 2017

ОСОБЕННОСТИ ХИМИЧЕСКОГО СОСТАВА И КАЧЕСТВА ВОДЫ В БАССЕЙНЕ РЕКИ ЛЕНЫ

Introduction. The Lena River is one of the largest rivers in Russia and the main transport artery of Yakutia. Methods. In the course of the study, we considered the water regime of the Lena River in 1981–2019 in relation to the monthly average water discharge. The hydrochemical runoff was quantitatively assessed based on the widely used landscape-hydrological method. The analysis made it possible to estimate the relationship between the natural water quality and the environmental state of catchments. Results. An increase in the winter temperature reduced the depth of soil freezing and increased the drainage properties of soil as well as the number and duration of winter thaws. The most pronounced annual water discharge was observed in the Aldan River basin in the eastern part of the Lena River basin. The current state of the surface water quality was assessed by the main hydrochemical characteristics: water salinity, principal ions (sulfates (SO4 2–)), nutrients (nitrite nitrogen (NO2–)), organic matter (BOD5 and COD), oil products, phenols, and iron (Fe) and copper (Cu) compounds. The water has quality class 3 and is characterized as “polluted” or “very polluted” in different zones of the river basin, with the situation being most acute in the Olekma River. Conclusions. We present the results of an analysis of the spatial and temporal variations in the content of the most informative hydrochemical components for two periods (2001–2009 and 2010–2019) in the Lena River basin in accordance with the most stringent commercial fishing standards in force. We also plotted and mapped the temporal variations in the main pollutants. Graphs and maps of the time dynamics of the main pollutants are constructed.