Ship Traffic in the Asian Arctic Seas

<p><span>Discharges from the largest rivers of the World to coastal sea form sea-wide freshened surface layers which areas have order of hundred thousands of square kilometers. Large freshened surface layers (which are among the largest in the World Ocean) are located in the Kara, Laptev, and East-Siberian seas in the Eastern Arctic. </span><span>This work is focused on the structure and inter-annual variability of these freshened water masses during ice-free periods. The freshened surface layer in the Laptev and East-Siberian seas is formed mainly by deltaic rives among which the Lena River contributes about two thirds of the inflowing freshwater volume. Based on in situ measurements, we show that the area of this freshened surface layer is much greater than the area of the freshened surface layer in the neighboring Kara Sea, while the total annual freshwater discharge to the Laptev and East-Siberian seas is 1.5 times less than to the Kara Sea (mainly from the estuaries of the Ob and Yenisei rivers). This feature is caused by differences in morphology of the estuaries and deltas. Shallow and narrow channels of the Lena Delta are limitedly affected by sea water. As a result, undiluted Lena discharge inflows to sea from multiple channels and forms relatively shallow plume, as compared to the Ob-Yenisei plumes which mix with subjacent saline sea water in deep and wide estuaries. The shallow Lena plume spreads over wide area (up to 500 000 km<sup>2</sup>) in the Laptev and East-Siberian seas during and shortly after freshet period in summer and then transforms to the Laptev/East-Siberian ROFI in autumn. Area and position of the relatively shallow freshened surface layer in the Laptev and East-Siberian seas have large inter-annual variability governed by local wind forcing conditions, however, do not show any dependence on significant variability of the annual volume of discharge rate from the Lena River. The deep freshened surface layer in the Kara Sea also has distinct seasonal varability of area and position, however, is stable on inter-annual time scale.<br></span></p>

In the Arctic, global warming is 2–3 times faster than over other regions of the globe. As a result, noticeable changes are already being recorded in all areas of the environment. However, there is very little data on such changes in the Russian Arctic. Therefore, to fill the gap in the data on the vertical distribution of the gas and aerosol composition of air in this region, an experiment was carried out on the Tu-134 Optik flying laboratory in September 2020 to sound the atmosphere and water surface over the water areas of all seas in the Russian Arctic. This paper analyzes the spatial distribution of methane. It is shown that during the experiment its concentration was the highest over the Kara Sea (2090 ppb) and the lowest over the Chukchi Sea (2005 ppb). The East Siberian and Bering Seas were slightly different from the Chukchi Sea in terms of the methane concentration. Average values of CH4 are characteristic of the Barents (2030 ppb) and the Laptev Seas (2040 ppb). The difference between the concentrations at an altitude of 200 meters and in the free troposphere attained 150 ppb over the Kara Sea, decreased to 91 and 94 ppb over the Barents and Laptev Seas, and further decreased over the East Siberian, Chukchi, and Bering Seas to 66, 63, and 74 ppb, respectively. Horizontal heterogeneity in the distribution of methane over the Arctic seas is the greatest over the Laptev Sea, where it attained 73 ppb. It is two times higher than over the Barents and Kara Seas, and 5–7 times higher than over the East Siberian and Bering Seas.

Fram Strait sea-ice sediments (SIS) contain on average more than 94% silt and clay. Both fractions were compared with bottom deposits of the Kara and Laptev seas to identify shelf sources of fine-grained Arctic SIS. Based on silt granulometry and clay mineral assemblages we determined Fram Strait SIS provinces. Western Fram Strait SIS has medium to fine silt compositions, whereas eastern Fram Strait SIS is enriched in fine silt.Western Fram Strait SIS clays (low smectite/high illite) were statistically grouped with eastern Laptev shelf deposits, and are similar to East Siberian and North American shelf sources. Eastern Fram Strait SIS clays (high smectite/low illite) cluster with shelf deposits of the western Laptev Sea and the Kara Sea. We conclude that western Fram Strait pack ice consisted of a mixture of floes from the Laptev Sea and sources farther to the east during the 1997 and 1999 sampling periods. Eastern Fram Strait ice originated from sources towards the Kara Sea. There was an average annual flux of ca. 158 Tg (Mt) SIS export through Fram Strait during the late 1990s.We expect no qualitative changes in the SIS entrainment process (“suspension freezing”) with decreasing Arctic ice cover, although the process may increase through larger fetch. SIS incorporation and flux will be enhanced with increasing shelf open water during winter freezing, and with the current acceleration of the Transpolar Drift, but we speculate that the transport of SIS towards Fram Strait will be seasonally truncated with the onset of ice-free summers in the Arctic Ocean.

This paper identified an atmospheric circulation anomaly–dipole structure anomaly in the Arctic atmosphere and its relationship with winter sea ice motion, based on the International Arctic Buoy Program (IABP) dataset (1979–98) and datasets from the National Centers for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) for the period 1960–2002. The dipole anomaly corresponds to the second-leading mode of EOF of monthly mean sea level pressure (SLP) north of 70°N during the winter season (October–March) and accounts for 13% of the variance. One of its two anomalous centers is stably occupied between the Kara Sea and Laptev Sea; the other is situated from the Canadian Archipelago through Greenland extending southeastward to the Nordic seas. The dipole anomaly differs from one described in other papers that can be attributed to an eastward shift of the center of action of the North Atlantic Oscillation. The finding shows that the dipole anomaly also differs from the “Barents Oscillation” revealed in a study by Skeie. Since the dipole anomaly shows a strong meridionality, it becomes an important mechanism to drive both anomalous sea ice exports out of the Arctic Basin and cold air outbreaks into the Barents Sea, the Nordic seas, and northern Europe. When the dipole anomaly remains in its positive phase, that is, negative SLP anomalies appear between the Kara Sea and the Laptev Sea with concurrent positive SLP over from the Canadian Archipelago extending southeastward to Greenland, there are large-scale changes in the intensity and character of sea ice transport in the Arctic basin. The significant changes include a weakening of the Beaufort gyre, an increase in sea ice export out of the Arctic basin through Fram Strait and the northern Barents Sea, and enhanced sea ice import from the Laptev Sea and the East Siberian Sea into the Arctic basin. Consequently, more sea ice appears in the Greenland and the Barents Seas during the positive phase of the dipole anomaly. During the negative phase of the dipole anomaly, SLP anomalies show an opposite scenario in the Arctic Ocean and its marginal seas when compared to the positive phase, with the center of negative SLP anomalies over the Nordic seas. Correspondingly, sea ice exports decrease from the Arctic basin flowing into the Nordic seas and the northern Barents Sea because of the strengthened Beaufort gyre. The finding indicates that influences of the dipole anomaly on winter sea ice motion are greater than that of the winter AO, particularly in the central Arctic basin and northward to Fram Strait, implying that effects of the dipole anomaly on sea ice export out of the Arctic basin become robust. The dipole anomaly is closely related to atmosphere–ice–ocean interactions that influence the Barents Sea sector.

We present an analysis of observed long‐term (∼100 year) salinity trends on the freshwater‐dominated Siberian continental shelves. A multiple regression was performed in the White Sea (WS), the Kara Sea (KS), the Laptev Sea (LS), and the East Siberian Sea (ESS). Since 1930, the WS has gained freshwater while the ESS has lost it, consistent with river discharge trends over this period. Over the past 20 years, increases in both river discharge and direct precipitation can explain observed salinity decreases in the WS, but not in the KS. Salinity trends in the LS and ESS indicate that ocean circulation plays a dominate role in these areas, where in recent years freshwater has been diverted eastward along the coast, rather than northward toward the deep ocean.

Hard life in cold waters: Size distribution and gonads show that Greenland halibut temporarily inhabit the Siberian Arctic

A comparative analysis of the sea urchins fauna from Russian seas was carried out based using known published references and personal data by these authors. We analyzed the species diversity of sea urchins from the Arctic seas of Russia (White Sea, Barents Sea, Kara Sea, Laptev Sea, East-Siberian Sea, and Chukchi Sea), Far Eastern seas (Bering Sea, Sea of Okhotsk, Japan Sea) and the Central Polar Basin. In these areas, the sea urchins fauna can be clearly divided into 2 groups: 1) Arctic seas, 2) Far Eastern seas. Among the Far Eastern seas, the fauna from the Sea of Okhotsk and Japan Sea is most similar. Among the Arctic seas, the fauna of the Barents Sea is most different. Therefore, 2 groups can be distinguished: 1) Kara Sea, Laptev Sea and Central Polar Basin, 2) White Sea, East-Siberian Sea and Chukchi Sea.

<p>The Arctic is warming much faster than other regions of the globe. In 2020, temperature anomalies in the Russian Arctic reached unprecedented high levels. The atmospheric composition in this key region still remains insufficiently studied that makes difficult predicting future climate change.</p><p>In September 2020, an extensive aircraft campaign was conducted to document the tropospheric composition over the Russian Arctic. The Optik Tu-134 research aircraft was equipped with instruments to carry out in-situ measurements of trace gases and aerosols, as well as with a lidar for profiling of aerosol backscatter. The aircraft flew over a vast area from Arkhangelsk to Anadyr. Six measurement flights with changing altitudes from 0.2 to 9.0 m were conducted over the waters of the Barents, Kara, Laptev, East Siberian, Chukchi, and Bering Seas. The weather was unusually warm for this period of the year, surface air temperatures were above 0°C through the campaign.</p><p>Here, we present the results of in-situ measurements of the vertical distribution of aerosol number concentrations in a wide range of sizes. A modified diffusional particle sizer (DPS) consisted of the Novosibirsk-type eight-stage screen diffusion battery connected to the TSI condensation particle counter Model 3756 was used to determine the number size distribution of particles between 0.003 mm and 0.2 mm (20 size bins). Distribution of particles in the size range from 0.25 µm to 32 µm (31 size bins) was measured by means of the Grimm aerosol spectrometer Model 1.109.</p><p>The flights over Barents and Kara Seas were predominantly performed under clear sky or partly cloudy weather conditions. Number size distributions were wide representing particles of almost all aerosol fractions. When flying in the upper troposphere with a constant altitude over these seas, some cases of enhanced concentrations of nucleation and Aitken mode particles comparable to ones in the lower troposphere were recorded, suggesting in situ new particle formation was likely to be taking place via gas-to-particle conversion aloft.</p><p>East of the Kara Sea, flights were conducted under mostly cloudy conditions resulting in a lower median aerosol number concentration and narrower size distributions.</p><p>This work was supported by the Russian Foundation for Basic Research (Grant No. 19-05-50024).</p>

Major hydrocarbon reserves have been discovered and developed during the last 20 years in the Russian Arctic. Productive basins include the West Siberian, Pechora, and Vilyuy. Gas discoveries in the Anadyr basin are too new to be evaluated. Untested basins include the following: (1) onshore: Anabar, Lena delta, Indigirka, and Kolyma; and (2) offshore: Barents and Pechora Seas, Kara Sea, Laptev Sea, East Siberian Sea, Bering Sea, and Sea of Okhotsk. In the West Siberian basin, as of January 1, 1970, more than 40 oil fields and 50 gas fields had been found. Production is from Cretaceous and Jurassic paralic to nonmarine strata. At least 9 oil fields had reserves greater than 500 million bbl; 20 gas fields had reserves greater than 3.5 Tcf. Samotlor is the largest oil field with 15.1 billion bbl; Urengoy, the world's largest gas field, had 210 Tcf. Deepest production was from about 10,500 ft, but most production was shallower than 8,150 ft. The Pechora basin contained about 62 oil and gas fields productive from Devonian through Permian marine strata. Of these, 1 oil field contained more than 500 million bbl and 2 gas fields, more than 3.5 Tcf. Deepest production was from about 11,155 ft. The Yenesey-Khatanga trough contained several fields, but is relatively undeveloped. The Vilyuy basin contained about 41 gas fields, of which 2 gas fields contained more than 3.5 Tcf each in Triassic and Jurassic paralic strata. Deepest production was from about 9,840 ft. More than 200 structures remain to be tested in the 4 basins. Although deformed basement has been penetrated in several areas, particularly near basin margins, the basin centers have not been explored thoroughly. In most of the West Siberian basin, for example, 2,000-8,000 ft of section below the deepest producing zones has not been tested. In the West Siberian basin alone, proved plus probable oil reserves exceed 35 billion bbl, and proved plus potential gas reserves exceed 400 Tcf. If the results from the West Siberian, Vilyuy, and Pechora basins are indicative of Russian Arctic potential, a bright future could be in store for the Russian petroleum industry. Despite the high costs and enormous logistics problems involved in development of these remote permafrost areas, the Russians are well on their way in developing End_Page 2495------------------------------ the West Siberian fields. The first pipeline of 40-in. diameter was completed to the Omsk refinery in 1967, and a second pipeline, of 48-in. diameter, is under construction. Siberia already has achieved self-sufficiency and the flow of crude oil in the Trans-Siberian pipeline was reversed west of Omsk in the summer of 1970 so that surplus West Siberian crude now moves westward to European Russia instead of the previous eastward flow of Volga-Urals crude to Siberia. In the Pechora basin, development of the largest potential producer, the Usa field, was underway in 1970 and construction of a pipeline to the Yaroslavl refinery in central Russia was started. The gas of the Vilyuy basin at present is used only locally, in the city of Yakutsk. No specific plans for long-distance transmissio have been announced. End_of_Article - Last_Page 2496------------

Comparison study of the modern ostracod associations in the Kara and Laptev seas: Ecological aspects

The paper presents a comparative analysis of size and reproductive parameters of snow crab in the Barents and Kara Seas, estimated in the period 2005–2019. In the Kara Sea, females reach maturity when their carapace width (CW) is over 30 mm, and the carapace width at 50% maturation is 38 mm. In the Barents Sea, female crabs reach functional maturity when their CW 35 mm, and the carapace width at 50% maturation is significantly higher compared to the Kara Sea and is equal to 51 mm. The fecundity of individuals of the same size, caught in the Kara Sea, is slightly lower than the fecundity of individuals recorded in the Barents Sea. At the same time, the increase in the number of eggs with an increase in CW in females of the Kara and Barents Seas is linear and statistically different (ANCOVA, p = 0.0327): 27 and 22 thousand eggs with an increase in CW by 10 mm, respectively. Compared to snow crabs in other geographic regions, in the Kara Sea, the values of the studied snow crabs parameters were close to the values estimated for individuals of the Arctic eastern seas: the Chukchi Sea and the Beaufort Sea. Most of the parameters of the Barents Sea population were comparable with the parameters of the populations of the southern part of the native range (the Sea of Japan, North-West Atlantic). It was revealed that the near-bottom temperature is to a large extent a limiting factor affecting not only the distribution of snow crab in the regions of the Northeast Atlantic, but largely determines the features of its morphometric and reproductive parameters during the acclimatization of the species in the Kara and Barents Seas.

River plumes formed by the Ob, Yenisei, and Lena rivers in the Eurasian Arctic are among the largest river plumes globally in terms of area. In this article, a detailed analysis of newly available satellite-derived surface salinity data retrieved for the Eurasian Arctic is presented. Two dominant spreading types of the Ob–Yenisei plume in the Kara Sea are identified. Under westerly–southwesterly winds, the plume remains coastally trapped along the southern coast of the sea, propagates eastward toward the Vilkitskiy Strait and into the Laptev Sea. Its area scales linearly with the combined Ob–Yenisei river discharge volume. Under easterly–northeasterly winds, the Ob–Yenisei plume expands toward the central and northern Kara Sea. Strong northeasterly winds can drive its advection into the northern part of Kara Sea, with plume areas up to 320 thousand km 2 . In the Eastern Arctic, the Lena plume exhibits two patterns governed by the presence or absence of wind–driven advection from the Laptev Sea to the East Siberian Sea via the Sannikov and Laptev Straits, controlled by winds over the southeastern Laptev Sea. Within the East Siberian Sea, the Lena plume behaves largely independently and is primarily wind–forced. Its area could exceed 800 thousand km 2 and shows weak sensitivity to river discharge volume.

Abstract. The snow data from the Soviet airborne expeditions Sever in the Arctic collected over several decades in March, April and May have been analyzed in this study. The Sever data included more measurements and covered a much wider area, particularly in the Eurasian marginal seas (Kara Sea, Laptev Sea, East Siberian Sea and Chukchi Sea), compared to the Soviet North Pole drifting stations. The latter collected data mainly in the central part of the Arctic Basin. The following snow parameters have been analyzed: average snow depth on the level ice (undisturbed snow) height and area of sastrugi, depth of snow dunes attached to ice ridges and depth of snow on hummocks. In the 1970s–1980s, in the central Arctic, the average depth of undisturbed snow was 21.2 cm, the depth of sastrugi (that occupied about 30 % of the ice surface) was 36.2 cm and the average depth of snow near hummocks and ridges was about 65 cm. For the marginal seas, the average depth of undisturbed snow on the level ice varied from 9.8 cm in the Laptev Sea to 15.3 cm in the East Siberian Sea, which had a larger fraction of multiyear ice. In the marginal seas the spatial variability of snow depth was characterized by standard deviation varying between 66 and 100 %. The average height of sastrugi varied from 23 cm to about 32 cm with standard deviation between 50 and 56 %. The average area covered by sastrugi in the marginal seas was estimated to be 36.5 % of the total ice area where sastrugi were observed. The main result of the study is a new snow depth climatology for the late winter using data from both the Sever expeditions and the North Pole drifting stations. The snow load on the ice observed by Sever expeditions has been described as a combination of the depth of undisturbed snow on the level ice and snow depth of sastrugi weighted in proportion to the sastrugi area. The height of snow accumulated near the ice ridges was not included in the calculations because there are no estimates of the area covered by those features from the Sever expeditions. The effect of not including that data can lead to some underestimation of the average snow depth. The new climatology refines the description of snow depth in the central Arctic compared to the results by Warren et al. (1999) and provides additional detailed data in the marginal seas. The snow depth climatology is based on 94 % Sever data and 6 % North Pole data. The new climatology shows lower snow depth in the central Arctic comparing to Warren climatology and more detailed data in the Eurasian seas.

In this study, warm and moist air intrusions (WaMAI) over the Arctic Ocean sectors of Barents, Kara, Laptev, East Siberian, Chukchi and Beaufort Seas in recent 40 winters (from 1979 to 2018) are identified from ERA5 reanalysis using both Eulerian and Lagrangian views. The analysis shows that WaMAIs, fuelled by Arctic blockings, causes a relative surface warming and hence a sea ice reduction by exerting positive anomalies of net thermal irradiances and turbulent fluxes to the surface. Over Arctic Ocean sectors with land-locked sea ice in winter, such as Laptev, East Siberian, Chukchi and Beaufort Seas, total surface energy budget is dominated by net thermal irradiance. From a Lagrangian perspective, total water path (TWP) increases linearly with the downstream distance from the sea ice edge over the completely ice-covered sectors, inducing almost linearly increasing net thermal irradiance and total surface energy-budget. However, over the Barents Sea, with an open ocean to the south, total net surface energy-budget is dominated by the surface turbulent flux. With the energy in the warm-and-moist air continuously transported to the surface, net surface turbulent flux gradually decreases with distance, especially within the first 2 degrees north of the ice edge, inducing a decreasing but still positive total surface energy budget. The boundary-layer energy-budget patterns over the Barents Sea can be categorized into three classes: radiation-dominated, turbulence-dominated and turbulence-dominated with cold dome, comprising about 52 %, 40 % and 8 % of all WaMAIs, respectively. Statistically, turbulence-dominated cases with or without cold dome occur along with one order of magnitude larger large-scale subsidence than the radiation-dominated cases. For the turbulence-dominated category, larger turbulent fluxes are exerted to the surface, probably because of stronger wind shear. In radiation-dominated WaMAIs, stratocumulus develops more strongly and triggers intensive cloud-top radiative cooling and related buoyant mixing that extends from cloud top to the surface, inducing a thicker well-mixed layer under the cloud. With the existence of cold dome, fewer liquid water clouds were formed and less or even negative turbulent fluxes could reach the surface.

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.