{"type": "FeatureCollection", "features": [{"id": "20.500.14243/346510", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-06-23T16:26:32Z", "type": "Journal Article", "created": "2019-01-07", "title": "Quantifying Degradative Loss of Terrigenous Organic Carbon in Surface Sediments Across the Laptev and East Siberian Sea", "description": "Abstract

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\uffe2\uff80\uff90shelf, or buried in the sediments. While our understanding of the fate of permafrost\uffe2\uff80\uff90derived organic matter in shelf waters is improving, poor constraints remain regarding degradation in sediments. Here we use an extensive data set of organic carbon concentrations and isotopes (n\uffc2\uffa0=\uffc2\uffa0109) to inventory terrigenous organic carbon (terrOC) in surficial sediments of the Laptev and East Siberian Seas (LS\uffc2\uffa0+\uffc2\uffa0ESS). Of these ~2.7 Tg terrOC about 55% appear resistant to degradation on a millennial timescale. A first\uffe2\uff80\uff90order degradation rate constant of 1.5\uffc2\uffa0kyr\uffe2\uff88\uff921 is derived by combining a previously established relationship between water depth and cross\uffe2\uff80\uff90shelf sediment\uffe2\uff80\uff90terrOC transport time with mineral\uffe2\uff80\uff90associated terrOC loadings. This yields a terrOC degradation flux of ~1.7\uffc2\uffa0Gg/year from surficial sediments during cross\uffe2\uff80\uff90shelf transport, which is orders of magnitude lower than earlier estimates for degradation fluxes of dissolved and particulate terrOC in the water column of the LS\uffc2\uffa0+\uffc2\uffa0ESS. The difference is mainly due to the low degradation rate constant of sedimentary terrOC, likely caused by a combination of factors: (i) the lower availability of oxygen in the sediments compared to fully oxygenated waters, (ii) the stabilizing role of terrOC\uffe2\uff80\uff90mineral associations, and (iii) the higher proportion of material that is intrinsically recalcitrant due to its chemical/molecular structure in sediments. Sequestration of permafrost\uffe2\uff80\uff90released terrOC in shelf sediments may thereby attenuate the otherwise expected permafrost carbon\uffe2\uff80\uff90climate feedback.Climate warming is expected to destabilize permafrost carbon (PF\uffe2\uff80\uff90C) by thaw\uffe2\uff80\uff90erosion and deepening of the seasonally thawed active layer and thereby promote PF\uffe2\uff80\uff90C mineralization to CO2 and CH4. A similar PF\uffe2\uff80\uff90C remobilization might have contributed to the increase in atmospheric CO2 during deglacial warming after the last glacial maximum. Using carbon isotopes and terrestrial biomarkers (\uffce\uff9414C, \uffce\uffb413C, and lignin phenols), this study quantifies deposition of terrestrial carbon originating from permafrost in sediments from the Chukchi Sea (core SWERUS\uffe2\uff80\uff90L2\uffe2\uff80\uff904\uffe2\uff80\uff90PC1). The sediment core reconstructs remobilization of permafrost carbon during the late Aller\uffc3\uffb8d warm period starting at 13,000\uffc2\uffa0cal\uffc2\uffa0years before present (BP), the Younger Dryas, and the early Holocene warming until 11,000\uffc2\uffa0cal\uffc2\uffa0years BP and compares this period with the late Holocene, from 3,650\uffc2\uffa0years BP until present. Dual\uffe2\uff80\uff90carbon\uffe2\uff80\uff90isotope\uffe2\uff80\uff90based source apportionment demonstrates that Ice Complex Deposit\uffe2\uff80\uff94ice\uffe2\uff80\uff90 and carbon\uffe2\uff80\uff90rich permafrost from the late Pleistocene (also referred to as Yedoma)\uffe2\uff80\uff94was the dominant source of organic carbon (66\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%; mean\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0standard deviation) to sediments during the end of the deglaciation, with fluxes more than twice as high (8.0\uffc2\uffa0\uffc2\uffb1\uffc2\uffa04.6\uffc2\uffa0g\uffc2\uffb7m\uffe2\uff88\uff922\uffc2\uffb7year\uffe2\uff88\uff921) as in the late Holocene (3.1\uffc2\uffa0\uffc2\uffb1\uffc2\uffa01.0\uffc2\uffa0g\uffc2\uffb7m\uffe2\uff88\uff922\uffc2\uffb7year\uffe2\uff88\uff921). These results are consistent with late deglacial PF\uffe2\uff80\uff90C remobilization observed in a Laptev Sea record, yet in contrast with PF\uffe2\uff80\uff90C sources, which at that location were dominated by active layer material from the Lena River watershed. Release of dormant PF\uffe2\uff80\uff90C from erosion of coastal permafrost during the end of the last deglaciation indicates vulnerability of Ice Complex Deposit in response to future warming and sea level changes.The burial of terrestrial organic carbon (terrOC) in marine sediments contributes to the regulation of atmospheric CO2 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. For the World\uffe2\uff80\uff99s largest marginal sea, the East Siberian Arctic shelf, transport requires 3600\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff89300 years for the 600\uffe2\uff80\uff89km from the Lena River to the Laptev Sea shelf edge. TerrOC was reduced by ~85% during transit resulting in a degradation rate constant of 2.4\uffe2\uff80\uff89\uffc2\uffb1\uffe2\uff80\uff890.6\uffe2\uff80\uff89kyr\uffe2\uff88\uff921. Hence, terrOC degradation during cross-shelf transport constitutes a carbon source to the atmosphere over millennial time. For the contemporary carbon cycle on the other hand, slow terrOC degradation brings considerable attenuation of the decadal-centennial permafrost carbon-climate feedback caused by global warming.

Abstract. Thawing of permafrost carbon (PF-C) due to climate warming can remobilise considerable amounts of terrestrial carbon from its long term storage to the marine environment. PF-C can be then buried in sediments or remineralised to CO2 with implications for the carbon-climate feedback. Studying historical sediment records during past natural climate changes can help to understand the response of permafrost to current climate warming. In this study two sediment cores collected from the East Siberian Sea were used to study terrestrial organic carbon sources, composition and degradation during the past ~\u20099500\u2009cal\u2009yrs\u2009BP. The CuO-derived lignin and cutin products combined with \u03b413C suggest that there was a higher input of terrestrial organic carbon to the East Siberian Sea between ~\u20099500 and 8200\u2009cal\u2009yrs\u2009BP than in all later periods. This high input was likely caused by marine transgression and permafrost destabilisation in the early Holocene climatic optimum. Based on source apportionment modelling using dual-carbon isotope (\u220614C, \u03b413C) data, coastal erosion releasing old Pleistocene permafrost carbon was identified as a significant source of organic matter translocated to the East Siberian Sea during the Holocene.

", "keywords": ["Environmental sciences", "TD172-193.5", "13. Climate action", "TD169-171.8", "SDG 13 - Climate Action", "GE1-350", "SDG 14 - Life Below Water", "14. Life underwater", "15. Life on land", "Environmental protection", "01 natural sciences", "Environmental pollution", "0105 earth and related environmental sciences"]}, "links": [{"href": "https://cp.copernicus.org/articles/13/1213/2017/cp-13-1213-2017.pdf"}, {"href": "https://doi.org/2591129867"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Climate%20of%20the%20Past", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "2591129867", "name": "item", "description": "2591129867", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/2591129867"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2017-02-21T00:00:00Z"}}, {"id": "2763277233", "type": "Feature", "geometry": null, "properties": {"license": "Closed Access", "updated": "2026-06-23T16:26:53Z", "type": "Journal Article", "created": "2017-10-02", "title": "Release of Black Carbon From Thawing Permafrost Estimated by Sequestration Fluxes in the East Siberian Arctic Shelf Recipient", "description": "Abstract

Black carbon (BC) plays an important role in carbon burial in marine sediments globally. Yet the sequestration of BC in the Arctic Ocean is poorly understood. Here we assess the concentrations, fluxes, and sources of soot BC (SBC)\uffe2\uff80\uff94the most refractory component of BC\uffe2\uff80\uff94in sediments from the East Siberian Arctic Shelf (ESAS), the World's largest shelf sea system. SBC concentrations in the contemporary shelf sediments range from 0.1 to 2.1\uffc2\uffa0mg\uffc2\uffa0g\uffe2\uff88\uff921\uffc2\uffa0dw, corresponding to 2\uffe2\uff80\uff9312% of total organic carbon. The 210Pb\uffe2\uff80\uff90derived fluxes of SBC (0.42\uffe2\uff80\uff9311\uffc2\uffa0g\uffc2\uffa0m\uffe2\uff88\uff922\uffc2\uffa0yr\uffe2\uff88\uff921) are higher or in the same range as fluxes reported for marine surface sediments closer to anthropogenic emissions. The total burial flux of SBC in the ESAS (~4,000\uffc2\uffa0Gg\uffc2\uffa0yr\uffe2\uff88\uff921) illustrates the great importance of this Arctic shelf in marine sequestration of SBC. The radiocarbon signal of the SBC shows more depleted yet also more uniform signatures (\uffe2\uff88\uff92721 to \uffe2\uff88\uff92896\uffe2\uff80\uffb0; average of \uffe2\uff88\uff92774\uffc2\uffa0\uffc2\uffb1\uffc2\uffa062\uffe2\uff80\uffb0) than of the non\uffe2\uff80\uff90SBC pool (\uffe2\uff88\uff92304 to \uffe2\uff88\uff92728\uffe2\uff80\uffb0; average of \uffe2\uff88\uff92491\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0163\uffe2\uff80\uffb0), suggesting that SBC is coming from an, on average, 5,900\uffc2\uffa0\uffc2\uffb1\uffc2\uffa0300\uffc2\uffa0years older and more specific source than the non\uffe2\uff80\uff90SBC pool. We estimate that the atmospheric BC input to the ESAS is negligible (~0.6% of the SBC burial flux). Statistical source apportionment modeling suggests that the ESAS sedimentary SBC is remobilized by thawing of two permafrost carbon (PF/C) systems: surface soil permafrost (topsoil/PF; 25\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%) and Pleistocene ice complex deposits (ICD/PF; 75\uffc2\uffa0\uffc2\uffb1\uffc2\uffa08%). The SBC contribution to the total mobilized permafrost carbon (PF/C) increases with increasing distance from the coast (from 5 to 14%), indicating that the SBC is more recalcitrant than other forms of translocated PF/C. These results elucidate for the first time the key role of permafrost thaw in the transport of SBC to the Arctic Ocean. With ongoing global warming, these findings have implications for the biogeochemical carbon cycle, increasing the size of this refractory carbon pool in the Arctic Ocean. Climate warming is expected to mobilize northern permafrost and peat organic carbon (PP-C), yet magnitudes and system specifics of even current releases are poorly constrained. While part of the PP-C will degrade at point of thaw to CO 2 and CH 4 to directly amplify global warming, another part will enter the fluvial network, potentially providing a window to observe large-scale PP-C remobilization patterns. Here, we employ a decade-long, high-temporal resolution record of 14 C in dissolved and particulate organic carbon (DOC and POC, respectively) to deconvolute PP-C release in the large drainage basins of rivers across Siberia: Ob, Yenisey, Lena, and Kolyma. The 14 C-constrained estimate of export specifically from PP-C corresponds to only 17 \uffc2\uffb1 8% of total fluvial organic carbon and serves as a benchmark for monitoring changes to fluvial PP-C remobilization in a warming Arctic. Whereas DOC was dominated by recent organic carbon and poorly traced PP-C (12 \uffc2\uffb1 8%), POC carried a much stronger signature of PP-C (63 \uffc2\uffb1 10%) and represents the best window to detect spatial and temporal dynamics of PP-C release. Distinct seasonal patterns suggest that while DOC primarily stems from gradual leaching of surface soils, POC reflects abrupt collapse of deeper deposits. Higher dissolved PP-C export by Ob and Yenisey aligns with discontinuous permafrost that facilitates leaching, whereas higher particulate PP-C export by Lena and Kolyma likely echoes the thermokarst-induced collapse of Pleistocene deposits. Quantitative 14 C-based fingerprinting of fluvial organic carbon thus provides an opportunity to elucidate large-scale dynamics of PP-C remobilization in response to Arctic warming. Biofouling proceeds in successive steps where the primary colonizers affect the phylogenetic and functional structure of a future microbial consortium. Using microbiologically influenced corrosion (MIC) as a study case, a novel approach for material surface protection is described, which does not prevent biofouling, but rather shapes the process of natural biofilm development to exclude MIC\uffe2\uff80\uff90related microorganisms. This approach interferes with the early steps of natural biofilm formation affecting how the community is finally developed. It is based on a multilayer artificial biofilm, composed of electrostatically modified bacterial cells, producing antimicrobial compounds, extracellular antimicrobial polyelectrolyte matrix, and a water\uffe2\uff80\uff90proof rubber elastomer barrier. The artificial biofilm is constructed layer\uffe2\uff80\uff90by\uffe2\uff80\uff90layer (LBL) by manipulating the electrostatic interactions between microbial cells and material surfaces. Field testing on standard steel coupons exposed in the sea for more than 30 days followed by laboratory analyses using molecular\uffe2\uff80\uff90biology tools demonstrate that the preapplied artificial biofilm affects the phylogenetic structure of the developing natural biofilm, reducing phylogenetic diversity and excluding MIC\uffe2\uff80\uff90related bacteria. This sustainable solution for material protection showcases the usefulness of artificially guiding microbial evolutionary processes via the electrostatic modification and controlled delivery of bacterial cells and extracellular matrix to the exposed material surfaces.