Carbonate Characteristics of the Gulf of Anadyr Waters

Doklady Earth Sciences - The first field data describing the dynamics of the carbonate system, the aragonite saturation state, and CO2 fluxes between the ocean and the atmosphere in the Gulf of...     

The degradation of submarine permafrost and the destruction of hydrates on the shelf of east arctic seas as a potential cause of the “Methane Catastrophe”: some results of integrated studies in 2011

On the basis of the analysis of published data and in the course of the authors’ long-term geochemical and acoustic surveys performed in 1995–2011 on the East Siberian shelf (ESS) and aimed to research the role of the Arctic shelf in the processes of massive methane outbursts into the Earth’s atmosphere, some crucially new results were obtained. A number of hypotheses were proposed concerning the qualitative and quantitative characterization of the scale of this phenomenon. The ESS is a powerful supplier of methane to the atmosphere owing to the continued degradation of the submarine permafrost, which causes the destruction of gas hydrates. The emission of methane in several areas of the ESS is massive to the extent that growth in the methane concentrations in the atmosphere to values capable of causing a considerable and even catastrophic warning on the Earth is possible. The seismic data were compared to those of the drilling from ice performed first by the authors in 2011 in the southeastern part of the Laptev Sea to a depth of 65 m from the ice surface. This made it possible to reveal some new factors explaining the observed massive methane bursts out of the bottom sediments.     

New data on the subaerial low-center-polygonal relief and factors controlling its transformation and current state on the East Siberian Shelf

The problem of the current state of subaerial morphosculptures on the periglacial East Siberian Shelf is still debatable due to the lack of in situ data. Therefore, any new information contributes to the knowledge of the evolution of the Arctic environment. In view of this, a complex of interdisciplinary oceanological studies was carried out in the southeastern part of the Laptev Sea. Using a side-scan sonar, images of the bottom surface were made, which show the shape of low-center-polygonal relief of the part of the modern coastal lowland area in the coastal zone near the area under study. Possible factors controlling the state of this morphosculpture within the East Siberian Shelf area of interest are considered.     

Lithological and Geochemical Characteristics of Morpholithogenesis in Buor-Khaya Bay

Oceanology - The paper presents the general lithological and geochemical characteristics of subsea permafrost and thawed bottom sediments from three cores drilled in Buor-Khaya Bay. The...     

Composition and genesis of the organic matter in the bottom sediments of the East Siberian Sea

The chemical composition of organic matter (C_org, N_org, δ¹³C, δ¹⁵N, and n-alkanes) was studied in the top layer of bottom sediments of the East Siberian Sea. Possible ways were proposed to estimate the amount of the terrigenous component in their organic matter (OM). The fraction of terrigenous OM estimated by the combined use of genetic indicators varied from 15% in the eastern part of the sea, near the Long Strait, to 95% in the estuaries of the Indigirka and Kolyma rivers, averaging 62% over the sea area.     

Distribution and air-sea fluxes of carbon dioxide on the Chukchi Sea shelf

This article presents the results of long-term studies of the dynamics of carbonate parameters and air–sea carbon dioxide fluxes on the Chukchi Sea shelf during the summer. As a result of the interaction of physical and biological factors, the surface waters on the west of Chukchi Sea were undersaturated with carbon dioxide when compared with atmospheric air; the partial pressure of CO₂ varied in the range from 134 to 359 μatm. The average value of CO₂ flux in the Chukchi Sea per unit area varied in the range from–2.4 to–22.0 mmol /(m² day), which is significantly higher than the average value of CO₂ flux in the World Ocean. It has been estimated that the minimal mass of C absorbed by the surface of Chukchi Sea from the atmosphere during ice-free season is 13 × 10¹² g; a great part of this carbon is transported to the deeper layers of sea and isolated from the atmosphere for a long period of time. The studies of the carbonate system of the Chukchi Sea, especially of its western part, will provide some new data on the fluxes of carbon dioxide in the Arctic Ocean and their changes. Our analysis can be used for an interpretation of the satellite assessment of CO₂ fluxes and dissolved CO₂ distribution in the upper layers of the ocean.     

Noble metals in the bottom sediments of the Chukchi Sea

Abundance of noble metals (NM) and bulk chemical composition have been studied in bottom sediments of the Chukchi Sea. Distribution of NM and their correlation with major and trace elements in the sediments have been analyzed using multicomponent statistics. It was established that the average contents of NM in the bottom sediments of the Chukchi Sea significantly exceed those both in shelf terrigenous sediments and stratisphere. Osmium and iridium enrich mixed and pelitic sediments relative to shallow-water areas and their influx is presumably determined by erosion of coastal and bottom loose deposits. High Ag, Ru, Au, and Pt contents were identified in the clayey sediments enriched in biogenic elements in the individual areas of the Southern Chukchi plain (Chukchi sea) confined to the intersection zones of submeridional and sublatitudinal structures of the graben-rift system, which was formed in the Mesozoic and activated in the late Cenozoic time.