Radioactivity of anthropogenic and natural radionuclides in marine sediments of the Chaun Bay, East Siberian Sea.

Natural radioactive isotopes serve as a useful proxy of geological and geochemical processes in marine environment, while radiocesium serves as an indicator of man-made contamination. Monitoring of natural and anthropogenic radioactivity under conditions of the climate changes in the Arctic region is of high importance in investigations of this natural system. For the first time, we report the data on spatial distribution of natural (Th, Ra, K) and anthropogenic (Cs) radionuclide activities in the marine sediments from Chaun Bay (East Siberian Sea).

Lithological and granulometric data for the upper sedimentary layer of the Chaun Bay, East Siberian Sea.

The article provides a data on 160 samples of bottom sediments obtained from 48 stations during 60th cruise of R/V Akademik Oparin in the East Siberian Sea in Autumn 2020 (26 September - 11 November). It contains mean diameter of the particles, sorting coefficient, standard deviation, skewness, and kurtosis, values of percentiles (p5, p10, p16, p25, p50, p75, p84, p90, p95), lithology and mass percentage of >2 mm, 1-2 mm, 0.5-1 mm, 250-500 µm, 125-250 µm, 63-125 µm, 31-63 µm, 10-31 µm, 2-10 µm, and <2 µm fractions.

The influence of sedimentation regime on natural radionuclide activity concentration in marine sediments of the East Siberian Arctic Shelf.

Transport and accumulation of radionuclides in the Arctic depends on many biogeochemical processes, which are changing at accelerated rates due to climate change and human economic activity. We present the results of a study on the features distribution of some natural radionuclides in the marine sediments on the East Siberian Arctic Shelf collected during several expeditions from 2008 to 2019. Average activity concentration of Th, K and Ra under the influence of different sedimentation regime increases from 40.

Siberian Arctic black carbon sources constrained by model and observation.

Black carbon (BC) in haze and deposited on snow and ice can have strong effects on the radiative balance of the Arctic. There is a geographic bias in Arctic BC studies toward the Atlantic sector, with lack of observational constraints for the extensive Russian Siberian Arctic, spanning nearly half of the circum-Arctic. Here, 2 y of observations at Tiksi (East Siberian Arctic) establish a strong seasonality in both BC concentrations (8 ng⋅m to 302 ng⋅m) and dual-isotope-constrained sources (19 to 73% contribution from biomass burning).

The East Siberian Arctic Shelf: towards further assessment of permafrost-related methane fluxes and role of sea ice.

Sustained release of methane (CH(4)) to the atmosphere from thawing Arctic permafrost may be a positive and significant feedback to climate warming. Atmospheric venting of CH(4) from the East Siberian Arctic Shelf (ESAS) was recently reported to be on par with flux from the Arctic tundra; however, the future scale of these releases remains unclear. Here, based on results of our latest observations, we show that CH(4) emissions from this shelf are likely to be determined by the state of subsea permafrost degradation.