Concentrations of trace elements in recent and preindustrial sediments from Norwegian and Russian Arctic lakes

1998 ◽  
Vol 55 (6) ◽  
pp. 1512-1523 ◽  
Author(s):  
Sigurd Rognerud ◽  
Trond Skotvold ◽  
Eirik Fjeld ◽  
Stephen A Norton ◽  
Anders Hobæk
Keyword(s):  
Organic Matter ◽  
Atmospheric Deposition ◽  
Surface Sediments ◽  
Arctic Lakes ◽  
The Arctic ◽  
Russian Arctic ◽  
Inorganic Matter ◽  
Sediment Data ◽  
Historic Change ◽  
Reference Sediment

Cu, Hg, Ni, Pb, Se, and Zn concentrations in surface and preindustrial freshwater sediments from 66 lakes in the Norwegian and Russian Arctic were used for studying modern atmospheric deposition of these elements. Statistical analysis showed that, after adjusting for the effects of scavenging factors in sediments (organic matter, Al, and Fe), there were, in general, significantly higher concentrations of Hg and Pb in surface sediments than preindustrial sediments. The differences decreased with increasing latitude and increasing longitude to the east, and in the lakes from arctic islands of Svalbard and along the the arctic coastline of Russia, only Hg concentrations were elevated in surface sediments. We attribute this pattern to modern anthropogenic atmospheric deposition. There were no such differences or regional gradients for the other trace metals. A multivariate analysis of the sediment data showed that Hg and Se were associated with organic matter, whereas Cu, Ni, and Zn were associated with inorganic matter (Al, Fe). There was a shift in Pb association from inorganic matter in the reference sediment to organic matter in the surface sediment, which we interpret as an historic change in importance of sources (from bedrock-derived to atmospheric deposition).

scholarly journals State of Lake Water Resources in the Russian Arctic Zone

2018 ◽  
Vol 64 (1) ◽  
pp. 84-100 ◽  
Author(s):  
V. A. Rumyantsev ◽  
A. V. Izmailova ◽  
L. N. Kryukov
Keyword(s):  
Water Resources ◽  
Russian Federation ◽  
Ecological Status ◽  
Arctic Lakes ◽  
Water Bodies ◽  
The Arctic ◽  
Russian Arctic ◽  
Arctic Zone ◽  
Arctic Regions ◽  
The Russian Federation

Regions of the Russian Federation classified among Arctic zone estimated to 22% of Russian territory. Arctic is characterized by the richest reserves of natural resources, and its phased, balanced development is the most important strategic task of Russia’s socioeconomic development. Production and household activities of the population of Russia living and working in the far North is associated with difficult climatic and geographical conditions. In this case, the constant cold and consumption of contaminated water can lead to aggravation of various human disease. The Arctic zone of the Russian Federation is characterized by the richness of water resources as rapidly renewable (river runoff and its underground component), and static one to which are assigned the waters of lakes, underground waters, waters (ice) of mountain and polar glaciers. A characteristic feature of water consumption in the Arctic regions is the active use of lake water, which in a number of settlements is the main source of drinking water supply. In this regard, the assessment of the lake’s fund of Arctic zone and its ecological status is extremely topical.According to the assessments, more than 2.5 million water bodies, that is a ~2/3 of all water bodies of the country, are decoded in the Arctic zone of the Russian Federation on satellite images. Mainly, these are small water bodies, only about 975 thousand of them exceed 1 ha. The total area of the water surface of Arctic lakes is ~160 thousand km2 (slightly less than a half of the total water surface of all natural water bodies of the Russian Federation), and the total volume of water enclosed in them is ~760 km3.Even in the middle of the 20th century, the lakes of the Russian Arctic, with rare exceptions, were characterized by the highest quality of their waters, but by now the ecological status of many water bodies has deteriorated significantly. The vulnerability of Arctic lakes to pollution is enhanced both by virtue of the peculiarities of their orometry and by the simplicity of the biological communities of northern ecosystems characterized by a low degree of stability. The poor knowledge of Arctic water bodies does not allow taking the necessary preventive measures for their protection and rational use. In this connection, attention to the expansion of works on the integrated study of limnology of water bodies included in the lake fund of the Arctic zone should be paid.An estimation of water resources of lakes of the Arctic zone of Russia, their ecological status and the questions of etiology of diseases on the territories of the Far North are given in this article. The morbidity of the population of the Arctic regions of Russia today is much higher than the national average. Further development of the territory and the observed warming of the climate will lead to increasing pollution of freshwater resources with toxic substances, pathogenic microorganisms and viruses. This will exacerbate the issue of ensuring environmental safety and meeting the needs of the population in quality drinking water. The situation is further aggravated by the fact that the most affordable technologies for water treatment and wastewater treatment in conditions of low temperatures and high content of humic substances in the initial water cannot ensure the proper level of disinfection. In this regard, one of the topical issues is the creation of innovative technologies for water purification that are more adequate to the conditions of the Arctic zone of Russia.

scholarly journals Characterization of particulate organic matter in the Lena River Delta and adjacent nearshore zone, NE Siberia – Part 1: Lignin-derived phenol compositions

2014 ◽  
Vol 11 (10) ◽  
pp. 14359-14411 ◽  
Author(s):  
M. Winterfeld ◽  
M. A. Goñi ◽  
J. Just ◽  
J. Hefter ◽  
G. Mollenhauer
Keyword(s):  
Organic Matter ◽  
Climate Warming ◽  
Catchment Area ◽  
Surface Sediments ◽  
The Arctic ◽  
Terrestrial Organic Matter ◽  
Small Catchment ◽  
Lena River ◽  
Diagenetic Alteration ◽  
Phenol Composition

Abstract. The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OM) from its vast catchment area to the coastal zone of the Laptev Sea and the Arctic Ocean. The permafrost soils of its far south stretching catchment, which store huge amounts of OM, will most likely respond differently to climate warming and remobilize previously frozen OM with distinct properties specific for the source vegetation and soil. To characterize the material discharged by the Lena River, we analyzed the lignin phenol composition in total suspended matter (TSM) from surface water collected in spring and summer, surface sediments from the Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex), and plant samples. Our results show that lignin-derived cinnamyl:vanillyl (C/V) and syringyl:vanillyl (S/V) ratios are >0.14 and 0.25, respectively, in TSM and surface sediments, whereas in delta soils they are >0.16 and >0.51, respectively. These lignin compositions are consistent with significant inputs of organic matter from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. We applied a simple linear mixing model based on the C/V and S/V ratios and the results indicate the organic matter in delta TSM samples and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm material, which is primarily derived from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small catchment area covered by tundra (∼12%), the input is substantial and tundra-derived OM input is likely to increase in a warming Arctic. The similar and high acid to aldehyde ratios of vanillyl and syringyl (Ad/AlV, S) in Lena Delta summer TSM (>0.7 and >0.5, respectively) and Buor Khaya Bay surface sediments (>1.0 and >0.9, respectively) suggest that the OM is highly degraded and Lena River summer TSM could be a possible source for the surface sediments. The Ad/AlV, S ratios of the first and third delta terraces were generally lower (mean ratios >0.4 and >0.4, respectively) than summer TSM and surface sediments. This implies that TSM contains additional contributions from a more degraded OM source (southern catchment and/or finer more degraded particle size). Alternatively, OM degradation on land after permafrost thawing and subaqueously during transport and sedimentation could be considerable. Despite the high natural heterogeneity of OM stored in delta soils and exported by the Lena River, the catchment characteristic vegetation is reflected by the lignin biomarker composition. Climate warming related changes in the Lena River catchment may be detectable in changing lignin biomarker composition and diagenetic alteration.

scholarly journals Characterising organic carbon sources in Anthropocene affected Arctic upland lake catchments, Disko Island, West Greenland

2020 ◽  
Author(s):  
Mark A. Stevenson ◽  
Suzanne McGowan ◽  
Emma J. Pearson ◽  
George E. A. Swann ◽  
Melanie J. Leng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Isotope Composition ◽  
Carbon Sources ◽  
Fold Increase ◽  
Arctic Lakes ◽  
Ice Age ◽  
The Arctic ◽  
Terrestrial Vegetation ◽  
Range Limit

Abstract. The Arctic is rapidly changing, disrupting biogeochemical cycles and the processing, delivery and sedimentation of carbon (C), in linked terrestrial-aquatic systems. In this investigation, we coupled a hydrogeomorphic assessment of catchment soils, sediments and plants with a recent lake sediment sequence to understand the source and quality of organic carbon present in three Arctic upland lake catchments on Disko Island, located just south of the Low-High Arctic transition zone. This varied permafrost landscape has exposed soils with less vegetation cover at higher altitudes, and all lakes received varying extent of glacial meltwater inputs. We provide improved isotope and biomarker source identifications for palaeolimnological studies in high latitude regions, where terrestrial vegetation is at or close to its northerly and altitudinal range limit. The poorly developed catchment soils lead to lake waters with low dissolved organic carbon (DOC) concentrations (≤ 1.5 mg L−1). Sedimentary Carbon / Nitrogen (C / N) ratios, the C isotope composition of organic matter (δ13Corg) and biomarker ratios (n-alkanes, n-alkanols, n-alkanoic acids and sterols) showed that sedimentary organic matter (OM) in these lakes is mostly derived from aquatic sources (algae and macrophytes). We used a 210 Pb dated sediment core to determine how carbon cycling in a lake-catchment system (Disko 2) had changed over recent centuries. Recent warming since the end of the Little Ice Age (LIA ~1860 AD), which accelerated after ca. 1950, led to melt of glacier ice and permafrost releasing nutrients and DOC to the lake, stimulating pronounced aquatic algal production, as shown by a > 10 fold increase in β-carotene, indicative of a major regime shift. Our findings highlight that in Arctic lakes with sparsely developed catchment vegetation and soils, recent Anthropocene warming results in pronounced changes to in-lake C processing and the deposition of more reactive, predominately autochthonous C, compared with extensively vegetated low Arctic systems.

Influence of Environmental Factors on Heavy Metal Concentration in Lake Sediments in Southern Norway Indicated by Path Analysis

1994 ◽  
Vol 51 (8) ◽  
pp. 1708-1720 ◽  
Author(s):  
Eirik Fjeld ◽  
Sigurd Rognerud ◽  
Eiliv Steinnes
Keyword(s):  
Organic Matter ◽  
Environmental Factors ◽  
Atmospheric Deposition ◽  
Path Analysis ◽  
Lake Sediments ◽  
Metal Concentration ◽  
Surface Sediments ◽  
Heavy Metal Concentration ◽  
Southern Norway ◽  
Positive Effect

We studied relationships between environmental factors and accumulation of Hg, Cd, Pb, and Ni in sediments in 132 lakes in southern Norway. Generally, the concentrations of Hg, Cd, and Pb in surface sediments were considerably elevated as compared with sediments deposited in preindustrial times whereas Ni concentrations showed only minor increases. By path analysis, we modelled how different environmental factors may influence the metal concentrations in surface sediments. The models indicated that both Hg and Pb were associated with sedimenting organic matter, and sediment concentrations were strongly influenced by atmospheric deposition (indirectly measured as metal concentration in mosses) and the amount of organic carrier particles in lake water. Cd behaved similarly, except for a weaker association with organic matter and a positive effect from pH, indicating that Cd is mobilized during acidification. Ni was associated with the inorganic fractions in lake sediments and seemed also to be mobilized during acidification. Geochemical contributions of Ni were larger in sediments than atmospheric deposition whereas atmospheric deposition was the major source of Pb. For the other two elements, estimates of geochemical contributions were lacking.

scholarly journals Evidence of Gas Emissions from Permafrost in the Russian Arctic

Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 383 ◽  
Author(s):  
Evgeny Chuvilin ◽  
Valentina Ekimova ◽  
Dinara Davletshina ◽  
Natalia Sokolova ◽  
Boris Bukhanov
Keyword(s):  
Natural Gas ◽  
Arctic Region ◽  
Arctic Lakes ◽  
The Arctic ◽  
Published Data ◽  
Permafrost Degradation ◽  
Russian Arctic ◽  
Gas Release ◽  
Gas Emissions ◽  
Ample Evidence

The active emission of gas (mainly methane) from terrestrial and subsea permafrost in the Russian Arctic has been confirmed by ample evidence. In this paper, a generalization and some systematization of gas manifestations recorded in the Russian Arctic is carried out. The published data on most typical gas emission cases have been summarized in a table and illustrated by a map. The tabulated data include location, signatures, and possible sources of each gas show, with respective references. All events of onshore and shelf gas release are divided into natural and man-caused. and the natural ones are further classified as venting from lakes or explosive emissions in dryland conditions that produce craters on the surface. Among natural gas shows on land, special attention is paid to the emission of natural gas from Arctic lakes, as well as gas emissions with craters formation. In addition, a description of the observed man-caused gas manifestations associated with the drilling of geotechnical and production wells in the Arctic region is given. The reported evidence demonstrates the effect of permafrost degradation on gas release, especially in oil and gas fields.

Tracing terrestrial organic matter in surface sediments in Laptev Sea and East Siberian Sea: a Rock-Eval pyrolysis approach

2020 ◽  
Author(s):  
Elena Gershelis ◽  
Roman Kashapov ◽  
Alexey Ruban ◽  
Andrey Grin'ko ◽  
Oleg Dudarev ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Surface Sediments ◽  
The Arctic ◽  
Laptev Sea ◽  
Residual Carbon ◽  
Terrestrial Organic Matter ◽  
East Siberian Sea ◽  
Carbon Compounds ◽  
Rock Eval

<p>The East Siberian Arctic shelf (ESAS), the world’s largest continental shelf, receives substantial input of terrestrial organic carbon (TerrOC) both from increasing river discharge and from amplifying coastal erosion. Increasing TerrOC supply directly affects the Arctic marine carbon cycle, and, therefore, the fate of TerrOC upon its translocation to the Arctic continental margin has been the subject of growing interest in recent decades. Previous studies reported a strong decrease in sedimentary bulk TerrOC and terrestrial biomarkers with increasing distance from the coast during cross-shelf transport with much higher extent of degradation in the ESAS nearshore zone. Despite major progress has been made in estimating TerrOC inputs and quantifying its degradation rates in the Arctic land-shelf system, there are still important pieces insufficiently understood. Rock-Eval (RE) pyrolysis contributes to the traditional geochemical interpretations, based on elemental, isotopic and biomarker analyses and provides additional insight into the distribution, source and degradation state of organic carbon compounds of sedimentary organic matter.</p><p>In this study, the analytical approach included the characterization of marine and terrestrial carbon compounds using RE data coupled with organic carbon stable isotope composition. Rock-Eval analyses was performed on over 80 surface sediments samples from the Laptev Sea and western part of the East Siberian Sea collected during Arctic expeditions in 2011-2019. A track of rapidly degrading terrOC in shallow deposits may be traced using the ratios between hydrogen and oxygen indices and from the distribution of labile organic carbon fraction. Our results indicated high content of heavily degraded material with low hydrogen index, high oxygen index and a high content of residual carbon in sediments on the outer shelf of the western Laptev Sea and on the continental slope. Sharp decreasing of oxygen content in the eastern part of Laptev Sea and the western East Siberian Sea marked intensive dilution of degraded carbon with fresher material exported from New Siberian Islands. Furthermore, the RE data indicated a relatively high content of residual carbon (up to 87 %) stored in the studied surface sediments.</p><p>This research is supported by Russian Science Foundation, project # 19-77-00067.</p>

Characteristics of organic carbon in surface sediments of Laptev Sea shelf

2020 ◽  
Author(s):  
Irina Oberemok ◽  
Elena Gershelis ◽  
Andrey Grin’ko ◽  
Alexey Ruban ◽  
Elizaveta Klevantseva ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Coastal Erosion ◽  
Surface Sediments ◽  
Oxygen Index ◽  
Outer Shelf ◽  
The Arctic ◽  
Laptev Sea ◽  
Shelf Sediments ◽  
The Laptev Sea

<p>Accelerating coastal erosion and enhancing river sediment discharge are expected to greatly increase the delivery of terrestrial organic carbon (terrOC) to the Arctic Ocean. Remobilized terrOC may be buried in shallow or outer shelf sediments, degraded and translocated to the deeper basins, or remineralized in the water column causing a positive feedback to amplified global warming. The East Siberian Arctic Shelf (ESAS), represented by the Laptev Sea, the East Siberian Sea, and the Russian part of the Chukchi Sea, is the widest and shallowest continental shelf of the World Ocean. In the current study, we investigated surface sediment samples collected across the Laptev Sea shelf (from the coastline to the outer shelf) during the Arctic expedition onboard the Russian <em>R/V Academician M. Keldysh</em> during fall 2018.</p><p>We analyzed 16 samples for bulk (TOC, <em>δ</em>13C) and molecular (distribution and concentration of n-alkanes and PAHs) parameters. We also performed Rock-Eval (RE) analysis in order to compare its results with the signatures provided by traditional geochemical tracers and thereby to gain new insights into the sources of organic matter in modern surface sediments. In addition, a grain-size analysis was carried out to reveal hydrodynamic control on the organic carbon transport across the studied transect. Using a combination of traditional molecular interpretations (performed in this study and published earlier) and RE parameters (Hydrogen index, Oxygen index and T<sub>peak</sub>) we attempted to distinguish riverine input and coastal erosion and disentangle processes of terrOC degradation and its replacement with fresh/marine OC during cross-shelf transport. Overall, a strong decrease of terrigenous contribution to the sedimentary organic carbon was observed on molecular level with increasing distance from the coast. According to the RE data, intensive terrOC degradation takes place in the shallow and mid-shelf sediments which is traced by sharply increasing oxygen index. The clear correlation between OI and the clay content points toward the perception that mineral matrix do not seem to be such good protector as expected, and intensive microbial degradation of the sedimentary organic matter contained in fine particles occurs during repeated resuspension.</p><p>This research is supported by Russian Science Foundation, project # 19-77-00067.</p>

scholarly journals Characterization of particulate organic matter in the Lena River delta and adjacent nearshore zone, NE Siberia – Part 2: Lignin-derived phenol compositions

2015 ◽  
Vol 12 (7) ◽  
pp. 2261-2283 ◽  
Author(s):  
M. Winterfeld ◽  
M. A. Goñi ◽  
J. Just ◽  
J. Hefter ◽  
G. Mollenhauer
Keyword(s):  
Organic Matter ◽  
Climate Warming ◽  
Catchment Area ◽  
Surface Sediments ◽  
The Arctic ◽  
Terrestrial Organic Matter ◽  
Small Catchment ◽  
Lena River ◽  
Diagenetic Alteration ◽  
Phenol Composition

Abstract. The Lena River in central Siberia is one of the major pathways translocating terrestrial organic matter (OM) from its vast catchment area to the coastal zone of the Laptev Sea and the Arctic Ocean. The permafrost soils of its far south-stretching catchment, which store huge amounts of OM, will most likely respond differently to climate warming and remobilize previously frozen OM with distinct properties specific for the source vegetation and soil. To characterize the material discharged by the Lena River, we analyzed the lignin phenol composition in total suspended matter (TSM) from surface water collected in spring and summer, surface sediments from Buor Khaya Bay along with soils from the Lena Delta's first (Holocene) and third terraces (Pleistocene ice complex), and plant samples. Our results show that lignin-derived cinnamyl : vanillyl (C / V) and syringyl : vanillyl (S / V) ratios are > 0.14 and 0.25, respectively, in TSM and surface sediments, whereas in delta soils they are > 0.16 and > 0.51, respectively. These lignin compositions are consistent with significant inputs of organic matter from non-woody angiosperm sources mixed with organic matter derived from woody gymnosperm sources. We applied a simple linear mixing model based on the C / V and S / V ratios, and the results indicate the organic matter in delta TSM samples and Buor Khaya Bay surface sediments contain comparable contributions from gymnosperm material, which is primarily derived from the taiga forests south of the delta, and angiosperm material typical for tundra vegetation. Considering the small catchment area covered by tundra (~ 12%), the input is substantial and tundra-derived OM input is likely to increase in a warming Arctic. The similar and high acid to aldehyde ratios of vanillyl and syringyl (Ad / AlV, S) in Lena Delta summer TSM (> 0.7 and > 0.5, respectively) and Buor Khaya Bay surface sediments (> 1.0 and > 0.9, respectively) suggest that the OM is highly degraded and Lena River summer TSM could be a possible source of the surface sediments. The Ad / AlV, S ratios of the first and third delta terraces were generally lower (mean ratios > 0.4 and > 0.4, respectively) than summer TSM and surface sediments. This implies that TSM contains additional contributions from a more degraded OM source (southern catchment and/or finer more degraded particle size). Alternatively, OM degradation on land after permafrost thawing and subaqueously during transport and sedimentation could be considerable. Despite the high natural heterogeneity of OM stored in delta soils and exported by the Lena River, the catchment-characteristic vegetation is reflected by the lignin biomarker composition. Climate-warming-related changes in the Lena River catchment may be detectable in changing lignin biomarker composition and diagenetic alteration.

scholarly journals Anthropocene climate warming enhances autochthonous carbon cycling in an upland Arctic lake, Disko Island, West Greenland

2021 ◽  
Vol 18 (8) ◽  
pp. 2465-2485
Author(s):  
Mark A. Stevenson ◽  
Suzanne McGowan ◽  
Emma J. Pearson ◽  
George E. A. Swann ◽  
Melanie J. Leng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Carbon Cycling ◽  
Vegetation Cover ◽  
Isotope Composition ◽  
Arctic Lakes ◽  
Ice Age ◽  
The Arctic ◽  
Terrestrial Vegetation ◽  
Range Limit

Abstract. The Arctic is rapidly changing, disrupting biogeochemical cycles and the processing, delivery and sedimentation of carbon (C), in linked terrestrial–aquatic systems. In this investigation, we coupled a hydrogeomorphic assessment of catchment soils, sediments and plants with a recent lake sediment sequence to understand the source and quality of organic carbon present in three Arctic upland lake catchments on Disko Island, located just south of the low–high Arctic transition zone. This varied permafrost landscape has exposed soils with less vegetation cover at higher altitudes, and lakes received varying amounts of glacial meltwater inputs. We provide improved isotope and biomarker source identifications for palaeolimnological studies in high-latitude regions, where terrestrial vegetation is at or close to its northerly and altitudinal range limit. The poorly developed catchment soils lead to lake waters with low dissolved organic carbon (DOC) concentrations (≤1.5 mg L−1). Sedimentary carbon/nitrogen (C/N) ratios, the C isotope composition of organic matter (δ13Corg) and biomarker ratios (n-alkanes, n-alkanols, n-alkanoic acids and sterols) showed that sedimentary organic matter (OM) in these lakes is mostly derived from aquatic sources (algae and macrophytes). We used a 210Pb-dated sediment core to determine how carbon cycling in a lake–catchment system (Disko 2) had changed over recent centuries. Recent warming since the end of the Little Ice Age (LIA∼1860 CE), which accelerated after ca. 1950, led to melt of glacier ice and permafrost, releasing nutrients and DOC to the lake and stimulating pronounced aquatic algal production, as shown by a >10-fold increase in β-carotene, indicative of a major regime shift. We also demonstrate that recent increases in catchment terrestrial vegetation cover contributed to the autochthonous response. Our findings highlight that in Arctic lakes with sparsely developed catchment vegetation and soils, recent Anthropocene warming results in pronounced changes to in-lake C processing and the deposition of more reactive, predominately autochthonous C, when compared with extensively vegetated low-Arctic systems.

Diatoms and aquatic palynomorphs in the sediments of the Eurasian Arctic seas and their significance for paleooceanological investigations in the Arctic

2019 ◽  
pp. 246-251
Author(s):  
Yelena I. Polyakova ◽  
Yekaterina I. Novichkova ◽  
Tatiana S. Klyuvitkina ◽  
Elizaveta A. Agafonova ◽  
Irina M. Kryukova
Keyword(s):  
Bering Sea ◽  
Surface Sediments ◽  
Sea Water ◽  
The Arctic ◽  
Marginal Filter ◽  
Arctic Seas ◽  
Hydrological Parameters ◽  
The Arctic Ocean ◽  
Long Term Studies

Presented the results of long-term studies of diatoms and aquatic palynomorphs in surface sediments of the Arctic seas and the possibility of their use for the reconstructions of paleocirculation water masses, advection of Atlantic and Bering sea water into the Arctic ocean, changes in the river runoff to the seas, sedimentary processes in the marginal filter of the largest rivers, seasonal sea ice cover and other hydrological parameters.

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