Onboard Large-Scale Isolation and Characterization of Three Reference DOM Materials from Siberian Arctic Shelf Marine Water.

The Siberian Arctic Shelf is undergoing major climate change in the Northern Hemisphere, heavily impacted by a massive release of dissolved organic matter (DOM) due to degradation of permafrost as a consequence of global warming. This work is devoted to the isolation of large quantities of DOM from the Kara Sea, the Laptev Sea, and the East Siberian Sea, located from west to east along the Siberian Arctic Shelf. The goal was to isolate Arctic marine water reference DOM materials, addressing the gap in the set of available reference DOM materials.

Distribution of dissolved trace elements in the Laptev Sea affected by the Lena River discharge.

This study presents new data on concentration of dissolved trace elements (DTE) in the Lena River-Laptev Sea mixing zone. Mean concentrations of some dissolved heavy metals in the mixing zone of fresh waters of the Lena River and sea waters of the Laptev Sea on the middle shelf and on the outer shelves are: 0.7± 0.

The Finding of Pogonophorans (Annelida, Siboglinidae) in the St. Anna Trough (Kara Sea) in an Area of Gas Hydrate Dissociation.

Representatives of pogonophorans (Annelida, Siboglinidae), whose vital activity is provided by symbiotic chemoautotrophic bacteria that oxidize methane and hydrogen sulfide, were found in the St. Anna Trough at depths of 539 and 437 m. The finding of pogonophorans suggests high concentrations of methane, which might result from dissociation of bottom gas hydrates under the influence of the influx of warm Atlantic water into the Kara Sea along the St.

A Complex of Marine Geophysical Methods for Studying Gas Emission Process on the Arctic Shelf.

The Russian sector of the arctic shelf is the longest in the world. Quite a lot of places of massive discharge of bubble methane from the seabed into the water column and further into the atmosphere were found there. This natural phenomenon requires an extensive complex of geological, biological, geophysical, and chemical studies.

Biogeochemical Activity of Methane-Related Microbial Communities in Bottom Sediments of Cold Seeps of the Laptev Sea.

Bottom sediments at methane discharge sites of the Laptev Sea shelf were investigated. The rates of microbial methanogenesis and methane oxidation were measured, and the communities responsible for these processes were analyzed. Methane content in the sediments varied from 0.

Circum-Arctic release of terrestrial carbon varies between regions and sources.

Arctic change is expected to destabilize terrestrial carbon (terrOC) in soils and permafrost, leading to fluvial release, greenhouse gas emission and climate feedback. However, landscape heterogeneity and location-specific observations complicate large-scale assessments of terrOC mobilization. Here we reveal differences in terrOC release, deduced from the Circum-Arctic Sediment Carbon Database (CASCADE) using source-diagnostic (δC-ΔC) and carbon accumulation data.

Data of polycyclic aromatic hydrocarbons concentration in the Siberian Arctic seas sediments.

Polycyclic Aromatic Hydrocarbons (PAHs) are one of the most dangerous persistent organic pollutants in the Arctic. They have different sources and pathways of entering in to the environment. Because of their lipophilic properties, PAHs can easily accumulate in marine sediments.

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.

Polycyclic aromatic hydrocarbons in the Siberian Arctic seas sediments.

Polycyclic Aromatic Hydrocarbons (PAHs) are among the main persistent organic pollutants in the Arcticwhich enter the polar region from lower latitudes by air transport and ocean currents and accumulate in marine sediments. This work represents the first study in 25 years of the least studied and hard-to-reach areas of Siberian arctic seas. Sixteen priority PAHs as well as 1- and 2-methylnaphthalenes were analyzed by gas chromatography - tandem mass spectrometry in the twenty-four sediment samples taken from Kara, Laptev and East Siberian Seas in October 2020.

World scientists' warnings into action, local to global.

'We have kicked the can down the road once again - but we are running out of road.' - Rachel Kyte, Dean of Fletcher School at Tufts University.We, in our capacities as scientists, economists, governance and policy specialists, are shifting from warnings to guidance for action before there is no more 'road.

Distribution of floating marine macro-litter in relation to oceanographic characteristics in the Russian Arctic Seas.

The main objectives of this work were the acquisition of new data on floating marine macro litter (FMML) and natural floating objects in the Arctic seas, an initial assessment of the level of pollution by FMML and an analysis of potential sources. The results of this study present the first data on FMML distribution in Russian Arctic shelf seas in relation to oceanographic conditions (i.e.

Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf.

The East Siberian Arctic Shelf holds large amounts of inundated carbon and methane (CH). Holocene warming by overlying seawater, recently fortified by anthropogenic warming, has caused thawing of the underlying subsea permafrost. Despite extensive observations of elevated seawater CH in the past decades, relative contributions from different subsea compartments such as early diagenesis, subsea permafrost, methane hydrates, and underlying thermogenic/ free gas to these methane releases remain elusive.

Remobilization of dormant carbon from Siberian-Arctic permafrost during three past warming events.

Carbon cycle models suggest that past warming events in the Arctic may have caused large-scale permafrost thaw and carbon remobilization, thus affecting atmospheric CO levels. However, observational records are sparse, preventing spatially extensive and time-continuous reconstructions of permafrost carbon release during the late Pleistocene and early Holocene. Using carbon isotopes and biomarkers, we demonstrate that the three most recent warming events recorded in Greenland ice cores-(i) Dansgaard-Oeschger event 3 (~28 ka B.

Freshwater transport between the Kara, Laptev, and East-Siberian seas.

The Kara and Laptev seas receive about one half of total freshwater runoff to the Arctic Ocean from the Ob, Yenisei, and Lena rivers. Discharges of these large rivers form freshened surface water masses over wide areas in these seas. These water masses, i.

The International Bathymetric Chart of the Arctic Ocean Version 4.0.

Bathymetry (seafloor depth), is a critical parameter providing the geospatial context for a multitude of marine scientific studies. Since 1997, the International Bathymetric Chart of the Arctic Ocean (IBCAO) has been the authoritative source of bathymetry for the Arctic Ocean. IBCAO has merged its efforts with the Nippon Foundation-GEBCO-Seabed 2030 Project, with the goal of mapping all of the oceans by 2030.

Signatures of Molecular Unification and Progressive Oxidation Unfold in Dissolved Organic Matter of the Ob-Irtysh River System along Its Path to the Arctic Ocean.

The Ob-Irtysh River system is the seventh-longest one in the world. Unlike the other Great Siberian rivers, it is only slightly impacted by the continuous permafrost in its low flow. Instead, it drains the Great Vasyugan mire, which is the world largest swamp, and receives huge load of the Irtysh waters which drain the populated lowlands of the East Siberian Plain.

Quantifying Degradative Loss of Terrigenous Organic Carbon in Surface Sediments Across the Laptev and East Siberian Sea.

Ongoing permafrost thaw in the Arctic may remobilize large amounts of old organic matter. Upon transport to the Siberian shelf seas, this material may be degraded and released to the atmosphere, exported off-shelf, or buried in the sediments. While our understanding of the fate of permafrost-derived organic matter in shelf waters is improving, poor constraints remain regarding degradation in sediments.

Remobilization of Old Permafrost Carbon to Chukchi Sea Sediments During the End of the Last Deglaciation.

Climate warming is expected to destabilize permafrost carbon (PF-C) by thaw-erosion and deepening of the seasonally thawed active layer and thereby promote PF-C mineralization to CO and CH. A similar PF-C remobilization might have contributed to the increase in atmospheric CO during deglacial warming after the last glacial maximum. Using carbon isotopes and terrestrial biomarkers (ΔC, δC, and lignin phenols), this study quantifies deposition of terrestrial carbon originating from permafrost in sediments from the Chukchi Sea (core SWERUS-L2-4-PC1).

Source apportionment of circum-Arctic atmospheric black carbon from isotopes and modeling.

Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources were dominated by emissions from fossil fuel combustion in the winter and by biomass burning in the summer.

Bounding cross-shelf transport time and degradation in Siberian-Arctic land-ocean carbon transfer.

The burial of terrestrial organic carbon (terrOC) in marine sediments contributes to the regulation of atmospheric CO on geological timescales and may mitigate positive feedback to present-day climate warming. However, the fate of terrOC in marine settings is debated, with uncertainties regarding its degradation during transport. Here, we employ compound-specific radiocarbon analyses of terrestrial biomarkers to determine cross-shelf transport times.

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).