Научное сотрудничество: мониторинг вечной мерзлоты циркумполярной зоны и обмен данными

Scientific cooperation is a well-supported narrative and theme, but in reality, presents many challenges and counter-productive difficulties. Moreover, data sharing specifically represents one of the more critical cooperation requirements, as part of the “scientific method [which] allows for verification of results and extending research from prior results.” One of the important pieces of the climate change puzzle is permafrost. Currently, most permafrost data remain fragmented and restricted to national authorities, including scientific institutes. Important datasets reside in various government or university labs, where they remain largely unknown or where access restrictions prevent effective use. A lack of shared research—especially data—significantly reduces effectiveness of understanding permafrost overall. Whereas it is not possible for a nation to effectively conduct the variety of modeling and research needed to comprehensively understand impacts to permafrost, a global community can. However, decision and policy makers, especially on the international stage, struggle to understand how best to anticipate and prepare for changes, and thus support for scientific recommendations during policy development. This article explores the global data systems on permafrost, which remain sporadic, rarely updated, and with almost nothing about the subsea permafrost publicly available. The authors suggest that the global permafrost monitoring system should be real time (within technical and reasonable possibility), often updated and with open access to the data. Following a brief background, this article will offer three supporting themes, 1) the current state of permafrost data, 2) rationale and methods to share data, and 3) implications for global and national interests.

Potential greenhouse gas production by organic matter decomposition in thawing subsea permafrost

<p>Subsea permafrost extends over vast areas across the East Siberian Arctic Ocean shelves and might harbor a large and vulnerable organic matter pool. Field campaigns have observed strongly elevated concentrations of CH<sub>4</sub> in seawater above subsea permafrost that might stem from microbial degradation of thawing subsea permafrost organic matter, from release of CH<sub>4</sub> stored within subsea permafrost, from shallow CH<sub>4</sub> hydrates or from deeper thermogenic/petrogenic CH<sub>4</sub> pools. We here assess the potential production of CH<sub>4</sub>, as well as CO<sub>2</sub> and N<sub>2</sub>O by organic matter degradation in subsea permafrost after thaw. To that end, we employ a set of subsea permafrost drill cores from the Buor-Khaya Bay in the south-eastern Laptev Sea where previous studies have observed a rapid deepening of the ice-bonded permafrost table. Preliminary data from an ongoing laboratory incubation experiment suggest the production of both CH<sub>4</sub> and CO<sub>2</sub> by decomposition of thawed subsea permafrost organic matter, while N<sub>2</sub>O production was negligible. These data will be combined with detailed biomarker analysis to constrain the vulnerability of subsea permafrost organic matter to degradation to greenhouse gases upon thaw.</p>

First experimental estimation of the methane ebullition fraction in water column from the bottom to the surface: application for the East Siberian Arctic Shelf

<p>The key area of the Arctic ocean for atmospheric venting of CH<sub>4</sub> is the East Siberian Arctic Shelf (ESAS). The ESAS covers >2 million square kilometers (equal to the areas of Germany, France, Great Britain, Italy, and Japan combined). This vast yet shallow region has recently been shown to be a significant modern source of atmospheric CH<sub>4</sub>, contributing annually no less than terrestrial Arctic ecosystems; but unlike terrestrial ecosystems, the ESAS emits CH<sub>4 </sub>year-round due to its partial openness during the winter when terrestrial ecosystems are dormant. Emissions are determined by and dependent on the current thermal state of the subsea permafrost and environmental factors controlling permafrost dynamics. Releases could potentially increase by 3-5 orders of magnitude, considering the sheer amount of CH<sub>4</sub> preserved within the shallow ESAS seabed deposits and the documented thawing rates of subsea permafrost reported recently.</p><p>The purpose of this work is to determine the methane ebullition fraction in water column: from the bottom to the surface, which is a key to evaluate quantitively methane release from the ESAS bottom through the water column into the atmosphere. A series of 351 experiments was carried out at to determine the quantity of methane (and other greenhouse gases) delivered by bubbles of various sizes through a water column into the atmosphere. It has been shown for depth up to 22 m (about 30% of the ESAS) that pure methane bubbles, depending on their diameter and water salinity, transported to the surface from 60.9% to 85.3% of gaseous methane.</p><p>This work was supported in part by grants from Russian Scientific Foundation (№ 18-77-10004 to DCh, DK, AK, № 19-77-00067 to EG), the Ministry of Science and Higher Education of the Russian Federation (grant ID: 075-15-2020-978 to IS). The work was carried out as a part of Federal[ПW1]  assignment № АААА-А17-117030110031-6 to AS.</p>

Modeling methane production and emission from thawing sub‐sea permafrost on the warming Arctic Shelf

<p>The Arctic shelf hosts a large, yet poorly quantified reservoir of relic permafrost. It has been suggested that global warming, which is amplified in polar regions, will accelerate the thawing of this subsea permafrost, thus potentially unlocking large stocks of comparably reactive organic matter (OM). The microbial degradation of OM in the thawing and generally anoxic permafrost layer has the potential of producing and, ultimately, releasing important fluxes of  CH<sub>4</sub> to the atmosphere. Because CH<sub>4</sub> is a potent greenhouse gas, such a release would further intensify global warming. However, the potential role of subsea permafrost thaw on microbial CH<sub>4</sub> production and CH<sub>4</sub> emissions from Arctic sediments currently remains unconstrained.<br>Here, we use a nested model approach to address this critical knowledge gap. We developed a pseudo-three-dimensional reaction-transport model for permafrost bearing sediments on the Arctic shelf to estimate the production, consumption, and, efflux of CH<sub>4</sub> on the Arctic shelf in response to projected subsea permafrost thaw. The model accounts for the most pertinent biogeochemical processes affecting methane and sulfur cycling in permafrost bearing marine sediments.                                                                <br>It is initialized based on a published submarine permafrost map (SuPerMap, [1]) and forced by a range of projected thawing rate scenarios derived from the Max Planck Institute Earth System Model (MPI-ESM) simulation results for the period 1850-2100. Critical model parameters, such as permafrost OM content and its apparent reactivity are chosen based on a comprehensive analysis of published experimental data. Here, we present the output of this environmental scenario ensemble.                                                <br>Simulation results reveal that CH<sub>4</sub> production rates are highly sensitive to changes in the apparent reactivity of permafrost OM. Although simulated CH<sub>4</sub> production rates vary over a large range (0.001-130 PgC produced over 250 years), they generally highlight the potential for producing and, thus releasing large amounts of methane from thawing subsea permafrost on the warming Arctic Shelf.</p><p>[1] Overduin, P. P., Schneider von Deimling, T., Miesner, F., Grigoriev, M. N., Ruppel, C. D., Vasiliev, A., et al. (2019).<br> Submarine permafrost map in the Arctic modeled using 1‐D transient heat flux (SuPerMAP). Journal of Geophysical Research: Oceans, 124, 3490–3507. https://doi.org/10.1029/2018JC014675<br><br></p>

Compositional pattern of lignin derived phenols of sediments as a proxy of accumulation of terrestrial organic matter in coastal zone of the Laptev Sea

<p>The modern East Siberian Arctic shelf represents a fascinating area with a vast expansion of subsea permafrost that holds a large pool of frozen immobilised organic carbon (OC). Amplified climate change at high latitudes has raised growing concerns about potential positive carbon–climate feedbacks. Degradation of permafrost in the Arctic could constitute a positive feedback to climate change due to activation of this OC stock, while recognizing the origin and peculiarities of organic matter (OM) is useful for predicting the potential for involving the ancient OC in modern carbon cycling. This paper emphasises the molecular composition of lignin-derived phenols (LDP) in bottom sediments and subsea permafrost from the Laptev Sea shelf as a proxy to describe the main sources, distribution, and preservation of terrestrial OM. The compositional pattern and concentration of LDP revealed irregular dynamics of terrigenous OM supply in the study area, that were governed primarily by continental flows. The OC concentration in the studied sediments varied from 0.04% to 23.1% (mean 1.74%, median 1.07%). The concentration of LDP in the studied 126 samples from five sediment cores obtained from Buor-Khaya Bay varied from 0.7 to 13191 (mean 539, median 63.5) µg/g of dry sediment as the sum of vanillyl, syringyl, and cinnamyl (VSC) compounds and from 0.03 to 27.6 (mean 1.61, median 0.76) mg/100 mg of OC content. All OC-rich samples showed higher concentrations of LDP and virtually non-oxidized lignin. Vegetation proxies suggested that vascular plant tissues account for a significant fraction of the lignin in the examined samples, with a strong share of gymnosperms. The concentration of LDP correlates to OC content, indicating a strong supply of terrestrial OC to the study area. Degradation proxies indicate a predominant supply of wood-rich non-oxidized terrestrial OM. The well-preserved lignin revealed in the studied deposits represents a specific feature of Quaternary lithodynamics of the Laptev Sea and is not typical for the majority of bottom sediments of the World Ocean. Good correlation between OC and lignin concentration suggests that terrigenous fluxes were the main contributor to OM supply. Distribution of specific lignin phenols and related ratios coupled with lithology and grain size revealed that fluvial processes have been leading here.</p><p>This research was supported through the Russian Scientific Foundation (grant no. 19-77-10044) within the framework of the state assignment of the Shirshov Institute of Oceanology RAS (grant no. 0149-2019-0006).</p>