Lena River Research Articles

Mathematical modeling of oil spill accidents during high water

Field pipeline failures can occur for various reasons during oil field development, resulting in emergency oil spills on the surface. In 2001, specialists from the State Committee on Ecology examined the Yamal-Nenets autonomous district and found that half of the areas with dense concentrations of wells referred to as "clusters," contained oil spills. In addition, considering the functioning characteristics of leaks at oil fields, the actual pollution area is estimated to be 2.5 to 10 times larger than what can be visually observed. According to some sources, by the early 2000s, approximately 350,000 kilometres of in-field and inter-field oil pipelines were operational in Russia. These field pipelines experienced between 50,000 to 60,000 failures each year, including ruptures and corrosion holes with leaks. The volume of oil spilt was estimated to range from 1% to 7% of the total production volume. It has been found that the annual discharge of oils and oil products from major rivers in Western Siberia into the Arctic seas amounts to: the Ob River contributes up to 600,000 tons, the Yenisei River up to 360,000 tons, and the Lena River up to 50,000 tons. In the Ob River basin alone, up to 1.5 million tons of oil are discharged each year, resulting in the loss of natural significance for approximately 250 rivers and 1,200 streams. Emergency leaks that occur in spring, when a layer of meltwater is present on the surface, can cause the oil slick to spread extensively due to wind effects, leading to uncontrolled environmental pollution. Oil slick movement on the water surface may extend to important protected areas, such as rivers, lakes, and streams, resulting in further contamination. Therefore, mathematical modelling of the emergency spread of spilt oil on a natural surface covered with meltwater is essential for addressing various situations in engineering practice. Predictive calculations using the proposed mathematical model allow for the evaluation of the oil slick's spread dynamics, providing the basis for necessary actions to localize the spill and prevent pollution of critical protected natural areas.Predictive calculations using this mathematical model can help evaluate the dynamics of the oil slick's spread, providing a basis for necessary actions to localize the spill and prevent pollution of critical protected natural areas.

Lena River biogeochemistry captured by a 4.5-year high-frequency sampling program

Abstract. The Siberian Arctic is warming rapidly, causing permafrost to thaw and altering the biogeochemistry of aquatic environments, with cascading effects on the coastal and shelf ecosystems of the Arctic Ocean. The Lena River, one of the largest Arctic rivers, drains a catchment dominated by permafrost. Baseline discharge biogeochemistry data are necessary to understand present and future changes in land-to-ocean fluxes. Here, we present a high-frequency 4.5-year-long dataset from a sampling program of the Lena River's biogeochemistry, spanning April 2018 to August 2022. The dataset comprises 587 sampling events and measurements of various parameters, including water temperature, electrical conductivity, stable oxygen and hydrogen isotopes, dissolved organic carbon concentration and 14C, colored and fluorescent dissolved organic matter, dissolved inorganic and total nutrients, and dissolved elemental and ion concentrations. Sampling consistency and continuity and data quality were ensured through simple sampling protocols, real-time communication, and collaboration with local and international partners. The data are available as a collection of datasets separated by parameter groups and periods at https://doi.org/10.1594/PANGAEA.913197 (Juhls et al., 2020b). To our knowledge, this dataset provides an unprecedented temporal resolution of an Arctic river's biogeochemistry. This makes it a unique baseline on which future environmental changes, including changes in river hydrology, at temporal scales from precipitation event to seasonal to interannual can be detected.

Small shelly fossils from the Kharayutekh Formation of the Upper Vendian period in the lower reaches of the Lena River in Eastern Siberia

Small shelly fossils from the Kharayutekh Formation of the Upper Vendian period in the lower reaches of the Lena River in Eastern Siberia

Carbon dioxide exchange across water–air interface and its influencing factors in middle reaches of Yellow River during winter

ABSTRACT River systems strongly contribute to CO2 emissions. However, despite numerous reports on gas emissions from ice, the current understanding of CO2 exchange of rivers in winter and the factors affecting it is still relatively limited. To shed light on CO2 exchange and the factors influencing it for rivers during winter. Based on intensive field measurements using floating chambers, riverine CO2 exchange in middle reaches of Yellow River in China was examined. Our results showed net emissions of CO2 across the ice-free interface (51.874∼162.478 mg/m²·h). Compared with other rivers worldwide, the CO2 exchange is higher than most major rivers, such as the Lena and Kolyma Rivers. However, at the ice-covered river monitoring site, CO2 exchange across the water–air interface exhibited a net uptake, ranging from −36.336 to 0 mg/m²·h. Furthermore, the relationships between CO2 exchange and relevant physicochemical variables showed that CO2 emissions negatively correlated with pH and ice thickness and positively correlated with water velocity, wind speed, water temperature, atmospheric temperature, ammonia nitrogen levels, and total phosphorous content. This study is scientifically valuable as the findings provide insight into the CO2 exchange pattern that occurs at the water–air interface of rivers during winter both ice-covered and ice-free sites.

ГЕОТЕРМИЧЕСКАЯ МОДЕЛЬ НЕФТЕГАЗОНОСНЫХ ОТЛОЖЕНИЙ ВИЛЮЙСКОЙ ГЕМИСИНЕКЛИЗЫ

The paper deals with the presented results of geothermal studies of Paleozoic and Mesozoic deposits within the Vilyuy hemisyneclise and adjacent territories. Features of geothermal zoning of oil-and-gas deposits are determined by the cryogenic stratum developed everywhere here, structural plan and heat flow magnitude. The lowest values of heat flow (up to 35 MW/m2) are typical for the western and south-western regions of the Vilyuy hemisyneclise, the largest (up to 50 MW/m2 or more) values are сharacteristic of central and eastern ones. The thickness of the cryogenic stratum naturally increases with a distance from the Lena River valley, where a through talik is developed, in a north-western direction, where it exceeds 1000 m; the thickness of the cryogenic stratum is 600–650 m in the central regions of the hemisyneclise. Two types of vertical geothermal zoning have been determined. The first type with low geothermal gradients (0.49–1.40 °C/100 m) was revealed in the southern, north-western and north-eastern margins; the second one (more than 2 °C/100 m) – throughout most of the studied region. The thermal regime of Cambrian rocks is significantly influenced by disjunctive tectonics, which is expressed in an increase in the values of current reservoir temperatures in the south-east of the research area (more than 180–190 °C).

The eastward intrusion of the Lena River into the East Siberian Sea since the early Holocene

The eastward intrusion of the Lena River into the East Siberian Sea since the early Holocene

Frazil ice changes winter biogeochemical processes in the Lena River

The ice-covered period of large Arctic rivers is shortening. To what extent will this affect biogeochemical processing of nutrients? Here we reveal, with silicon isotopes (δ30Si), a key winter pathway for nutrients under river ice. During colder winter phases in the Lena River catchment, conditions are met for frazil ice accumulation, which creates microzones. These are conducive to a lengthened reaction time for biogeochemical processes under ice. The heavier δ30Si values (3.5 ± 0.5 ‰) in river water reflect that 39 ± 11% of the Lena River discharge went through these microzones. Freezing-driven amorphous silica precipitation concomitant to increased ammonium concentration and changes in dissolved organic carbon aromaticity in Lena River water support microbially mediated processing of nutrients in the microzones. Upon warming, suppressing loci for winter intra-river nitrogen processing is likely to modify the balance between N2O production and consumption, a greenhouse gas with a large global warming potential.

Soils of Tundra and Sub-Tundra Larch Open Woodland of Tit-Ary Island (Delta of the Lena): Genesis, Properties, and Distribution Trends

Physico-chemical properties and vertical distribution patterns of clay minerals were studied in the permafrost affected soils from the tundra and sub-tundra larch open woodland of Tit-Ary island. That unique complex is located in the delta of the Lena river, Republic of Sakha (Yakutia). Despite the small size of the island and the fact that permafrost is close to the surface, several variants of pedogenesis determine the soil diversity in this area. The soils are characterized by various degrees of gleyic and stagnic properties due to sandy or loamy texture and location in the landscapes (top of the hills as well as steep or gentle slope). Mineral association is the same in the studied profiles characterized by the predominance of two components – chlorite and illite. Iron hydroxide–lepidocrocite occurred on the boundary of permanently frozen ground in the profile within pronounced spodic features as well as smectitic clay indentified in the both horizon of this permafrost affected soil can be attributed as a result of modern pedogenesis.

Impacts of spatially inconsistent permafrost degradation on streamflow in the Lena River Basin

Impacts of spatially inconsistent permafrost degradation on streamflow in the Lena River Basin

Response of the Cyanobacteria Plankton Community to Anthropogenic Impact in Small Lakes of Urbanized Territory in the Permafrost Zone of Northeast Asia (Eastern Siberia, Yakutia)

In the conditions of growing anthropogenic pressure, aquatic ecosystems all over the world are subject to transformation, expressed in the growth of eutrophication, increase in acidity, changes in water exchange, etc. In the region of Eastern Siberia we studied, located in Yakutia in the middle reaches of the Lena River basin, there is a significant population growth accompanied by advancements in agriculture and public utilities. The region is rich in small lakes, which have been under pressure from human activities for the past few decades. The studied region is located in the permafrost zone and is characterized by severe climatic conditions, cold long winters, short hot summers, and a short ice-free period on reservoirs. We studied 17 lakes of various genesis, with varying degrees of anthropogenic pressure, located in the largest city of the region, small villages, and at different distances from them. Previous studies have established that cyanobacteria constitute the phytoplankton main group in these lakes during the summer period. Therefore, we selected them as the focus for our bioindication analysis. An integrated assessment of the bioindication properties of cyanobacteria, along with chemical water parameters, was undertaken using statistical mapping methods, JASP, and Redundancy Analysis (RDA). This analysis revealed the impact of urbanized areas, characterized by a decrease in pH, runoff of nitrogen compounds, and an increase in organic matter. Despite the cryolithozone harsh conditions, in small lakes of urbanized areas, cyanobacteria exhibit their competitive advantages within the plankton community. The prospect of continuing our work is associated with the need to determine the risk of cyanoHAB development since potentially toxic cyanobacteria have a mass development in a number of lakes.

Feedbacks From Young Permafrost Carbon Remobilization to the Deglacial Methane Rise

AbstractThe abrupt warming events punctuating the Termination 1 (about 11.7–18 ka Before Present, BP) were marked by sharp rises in the concentration of atmospheric methane (CH4). The role of permafrost organic carbon (OC) in these rises is still debated, with studies based on top‐down measurements of radiocarbon (14C) content of CH4 trapped in ice cores suggesting minimum contributions from old and strongly 14C‐depleted permafrost OC. However, organic matter from permafrost can exhibit a continuum of 14C ages (contemporaneous to >50 ky). Here, we investigate the large‐scale permafrost remobilization at the Younger Dryas‐Preboreal transition (ca. 11.6 ka BP) using the sedimentary record deposited at the Lena River paleo‐outlet (Arctic Ocean) to reflect permafrost destabilization in this vast drainage basin. Terrestrial OC was isolated from sediments and characterized geochemically measuring δ13C, Δ14C, and lignin phenol molecular fossils. Results indicate massive remobilization of relatively young (about 2,600 years) permafrost OC from inland Siberia after abrupt warming triggered severe active layer deepening. Methane emissions from this young fraction of permafrost OC contributed to the deglacial CH4 rise. This study stresses that underestimating permafrost complexities may affect our comprehension of the deglacial permafrost OC‐climate feedback and helps understand how modern permafrost systems may react to rapid warming events, including enhanced CH4 emissions that would amplify anthropogenic climate change.

Geochemical Markers of Organic Matter Transformation in the Eastern Part of the Laptev Sea

The sources of supply and transformation of organic matter (OM) during the transition from the dissolved form to suspension, fluffy and bottom sediments on the meridional transect from the Lena River delta to the continental slope were described (depths from 10 to 2390 m, cruise 63 of the R/V Akademik Mstislav Keldysh, September 2015). The results of the study of OM molecular markers showed that dissolved and suspended OM of marine and terrigenous origin biodegrades in the water column and practically does not accumulate in bottom sediments. Thus, OM of the Lena river runoff does not contribute to the formation of OM in the bottom sediments in the summer period. On the outer shelf, an area of influence of ice bloom on the sedimentation process was revealed.

<i>Parnassia kotzebuei</i> (Parnassiaceae) at the western limit of its distribution

During a floristic survey of the territory of the mountain site "Sokol" of the Ust-Lensky Reserve, new localities of Parnassia kotzebuei were found at the western limit of its range, in the lower reaches of the Lena River. Previously, the limit of this species range was believed to be in the lower reaches of the Indigirka River. Parnassia kotzebuei is included in the list of rare and specially protected plants of the Republic of Sakha (Yakutia), is listed in the regional Red Data Books, and its presence on the territory of the Ust-Lensky Reserve will serve as an additional factor in ensuring the preservation of its populations. Hypotheses of the species appearance in this territory and its distribution in the adjacent area are expressed. Two possible versions are assumed: the relict (Pleistocene) origin of the populations, and the introduction of seeds by waterfowl beards. In both cases, the probability of its hydrochoric dissemination in the vicinity is allowed.

The structure of the upper part of the Earth’s crust in the area of the Lena River delta: the first magnetotelluric data

We present the first magnetotelluric sounding (MTS) data acquired in the southern part of the Lena River delta which is a junction zone of the Siberian Craton and the Verkhoyansk fold-and-thrust belt, in the transition zone from the Eurasian Continent to the shelf of the Laptev Sea. The MTS data were used to construct a vertical section of the bulk electrical resistivity (ER) structure of the Earth’s crust down to a depth of 8 km. The upper high-resistivity layer (320–000 Ohm m) corresponds to the permafrost rocks ranging in thickness from 1 km to 400 m under the channels of the Lena River. The underlying deformed Mesoproterozoic– Lower Triassic rocks can vary in composition, but they are poorly differentiated in ER values (110–40 Ohm m). We detected three low-resistivity anomalies (10–0 Ohm m) related to the fluid-saturated core and damage zones of active faults. A deep-lying high-resistivity anomaly (320–50 Ohm m) identified at the northeastern part of the section can correspond to the Lower Proterozoic or Archean metamorphic rocks.

New evidence on the structure and age of the Bestyakh Terrace of the Lena River (Ust-Buotama Outcrop)

New evidence on the structure and age of the Bestyakh Terrace of the Lena River (Ust-Buotama Outcrop)

Benthic communities under methane gradient in the Laptev and East Siberian seas

IntroductionMethane seeps influence surrounding benthic communities in different ways from slight changes in benthic abundance and biomass to major altering the species composition.Materials and MethodsWe studied benthic communities of 14 methane seep flares in Laptev and East Siberian seas with comparative analysis of species composition and abiotic parameters at the nearby areas not affected by methane seeps. The species diversity was comparable at seep and non-seep sites varying from 3.9 to 39.6 taxa per 100 individuals and from 4.5 to 34.8 taxa per 100 individuals, correspondingly.ResultsThe Laptev Slope community corresponds with the Polychaeta-community, encircling the upper continental slope area of the entire Siberian Arctic. The Lower Shelf community described in this study apparently corresponds with the Ophiocten sericeum community identified in the shelf areas of the Kara, Laptev and East Siberian seas. The Upper Shelf community is mostly inhabited by the bivalves species such as Portlandia arctica, Ennucula tenuis and Astarte montagui communities. The Estuarine community, which is the poorest by diversity but has high values of abundance and biomass is directly influenced by the Lena River runoff in terms of lower salinities and higher sedimentation rates.DiscussionThroughout the study area, the differences between the Estuarine, Upper Shelf, Lower Shelf and Laptev Slope communities exceeded the differences between the seep and background non-seep areas. Several taxa demonstrated correlations with different environmental factors, including the latitude, depth, temperature, salinity, pH and methane content, not depending on the revealed benthic community. Eight taxa demonstrated correlations with the methane content measured at different sediment depths. Two siboglinids taxa demonstrated high abundances at stations with highest methane content deep in the sediment. At the Siberian shelf, our geochemical data for siboglinid habitats are the first to be published so far.

Absolute dating of sediments forming the Lena river terraces (Northeastern Siberia)

Absolute dating of sediments forming the Lena river terraces (Northeastern Siberia)

Modeling Long-Term Dynamics of River Flow in the Lena River Basin Based on a Distributed Conceptual Runoff Model

Modeling Long-Term Dynamics of River Flow in the Lena River Basin Based on a Distributed Conceptual Runoff Model

The ways of penetration and prospects of invasion of the Asian badger <i>Meles leucurus</i> Hodgson 1847 (Carnivora, Mustelidae) into the territory of Yakutia

Two cases of the Asian badger findings in the territory of the South-Western Yakutia in 2000s were discussed, as well as the possibility of this species penetration into the taiga ecosystems of Yakutia. The findings were made in the Lena River valley and its left tributary, the Nyuya River. The most remote site is on the right side of the Lena River, over700 km downstream from the northernmost site where the species is reliably known to inhabit in the Lena River valley, and 300 km from the previous finding site in Yakutia (in the mid-20th century). The second site is located 80 km to the northwest of the first site, in the Nyuya River valley, 1 km from the nearest river, and 30 km from the Lena River. It can be assumed that the cases of badger migration to the territory of Yakutia are associated with climatic changes. There are three possible migration ways for the Asian badger from its primary geographic range into Yakutia: through the Lena River valley, where it can encounter biotopes resembling the forest-steppe habitats typical for this species; from the Nizhnyaya Tunguska River valley through the Nyuya and Chona Rivers into the valleys of the Lena and Vilyuy Rivers; and the third way, through the right-bank tributaries of the Lena River from the Patom Highlands. There are biotopes potentially suitable for the badger in the Central and Western Yakutia, but permafrost and limited food availability can be limiting factors hindering the expansion of the species northwards.

Application of remote sensing methods to assess the environmental situation in the upper Lena River basin

This article addresses the problem of pollution in the Lena River caused by gold mining enterprises operating in its upper regions. It highlights the ongoing industrial exploitation of ore and placer gold deposits in five regions within the Siberian and Far Eastern federal districts. The most large-scale development is carried out in the Irkutsk region, Buryatia, and Yakutia. Further intensification of gold mining activities will result in significant negative impacts on the ecosystems of the upper reaches of the Lena River basin. In this context, the potential applications of Sentinel-2 satellite data for assessing the ecological conditions of river systems in Yakutia are being explored. The most common water indices, NDTI, AMWI, and Harma, were used in this study. The indices were applied to analyze the area of the Vitim River mouth, which contains the highest concentration of active gold mining license areas in the basin. Test sites were allocated on the Vitim and Lena rivers, as well as on Lake Okhninskoye for control purposes. Water indices were analyzed using the ArcGIS software package, and statistical data processing was conducted in the MS Excel program. It is revealed that the best results for estimating surface water turbidity in the area of the Vitim River mouth are obtained using the AMWI index. Spatial regularities are demonstrated, and the seasonal dynamics of turbidity in the studied water bodies are analyzed. The proposed methodology using the AMWI index can be applied for operational assessment of the state of water bodies in Yakutia under conditions of active anthropogenic pollution. This can facilitate timely implementation of preventive environmental protection measures.