Onshore Thermokarst Primes Subsea Permafrost Degradation

Angelopoulos, Michael; Overduin, Paul; Jenrich, Maren; Nitze, Ingmar; Günther, Frank; Strauß, Jens; Westermann, Sebastian; Schirrmeister, Lutz; Холодов, А. С.; Krautblatter, Michael; Grigoriev, Mikhail N.; Grosse, Guido

doi:10.1029/2021gl093881

Cited by 13 publications

(10 citation statements)

References 66 publications

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“…Methane can also migrate upward from dissociating hydrates or free gas deposits due to increased permafrost permeability. The modeling results show that current permafrost is degrading due to flooding during the Holocene transgression by warm ocean waters [21,24,32].…”

Section: Spatial Distributions Of Submarine Permafrost and Model Sour...mentioning

confidence: 98%

“…The submarine permafrost formed during the Pleistocene glaciation periods can be distributed over a significant part of the Arctic shelf with water depths of up to 120-150 m (depending on the paleogeographic reconstructions), submerged due to the last postglacial transgression [18][19][20]. The formation of a sufficiently thick layer of seawater over permafrost leads to an increase in temperature at their upper boundary, contributing to the degradation of permafrost since its inundation [12,[21][22][23]. The submarine permafrost layer acts as a barrier to the underlying methane, which can be in the gaseous state or the form of hydrates.…”

Section: Introductionmentioning

confidence: 99%

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Model Study of the Effects of Climate Change on the Methane Emissions on the Arctic Shelves

Malakhova

Golubeva

2022

Atmosphere

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Based on a regional ice-ocean model, we simulated the state of the water masses of the Arctic Ocean to analyze the transport of dissolved methane on the Arctic shelves. From 1970 to 2019, we obtained estimates of methane emissions at the Arctic seas due to the degradation of submarine permafrost and gas release at the ocean–bottom interface. The calculated annual methane flux from the Arctic shelf seas into the atmosphere did not exceed 2 Tg CH4 yr−1. We have shown that the East Siberian shelf seas make the main contribution to the total methane emissions of the region. The spatial variability of the methane fluxes into the atmosphere is primarily due to the peculiarities of the water circulation and ice conditions. Only 7% of the dissolved methane originating from sediment enters the atmosphere within the study area. Most of it appears to be transported below the surface and oxidized by microbial activity. We found that increasing periods and areas of ice-free water and decreasing ice concentration have contributed to a steady increase in methane emissions since the middle of the first decade of the current century.

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Section: Spatial Distributions Of Submarine Permafrost and Model Sour...mentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Model Study of the Effects of Climate Change on the Methane Emissions on the Arctic Shelves

Malakhova

Golubeva

2022

Atmosphere

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“…In areas with ground ice, soil warming often triggers abrupt surface collapse, mass wasting, and coastal erosion (Kokelj and Jorgenson, 2013;Olefeldt et al, 2016;Grotheer et al, 2020;Angelopoulos et al, 2021). These thermokarst processes have a wide range of consequences depending on landscape position and soil characteristics (Mu et al, 2020a;Turetsky et al, 2020;Yang et al, 2021), including soil warming, GHG release or uptake, and delivery of sediment and solutes to aquatic ecosystems (Anthony et al, 2014;Abbott et al, 2015;Farquharson et al, 2019;Kokelj et al, 2021;Wologo et al, 2021;Yang et al, 2021).…”

Section: Unstable Footing: Terrestrial Permafrost Degradationmentioning

confidence: 99%

“…Consequently, climate change is intensifying disturbance regimes across the permafrost domain and restructuring socioecological dynamics at continental scales (Hjort et al, 2018;Chou et al, 2021;Veraverbeke et al, 2021;Treharne et al, 2022). In many regions, these changes are progressing decades faster than expected (Farquharson et al, 2019;Angelopoulos et al, 2021;Parkinson and DiGirolamo, 2021), likely heralding the transition of the permafrost domain into unprecedented biophysical and socioecological states (Box et al, 2019;IPCC, 2019;Meredith et al, 2019;Chen et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

We Must Stop Fossil Fuel Emissions to Protect Permafrost Ecosystems

Abbott

Brown²,

Carey

et al. 2022

Front. Environ. Sci.

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Climate change is an existential threat to the vast global permafrost domain. The diverse human cultures, ecological communities, and biogeochemical cycles of this tenth of the planet depend on the persistence of frozen conditions. The complexity, immensity, and remoteness of permafrost ecosystems make it difficult to grasp how quickly things are changing and what can be done about it. Here, we summarize terrestrial and marine changes in the permafrost domain with an eye toward global policy. While many questions remain, we know that continued fossil fuel burning is incompatible with the continued existence of the permafrost domain as we know it. If we fail to protect permafrost ecosystems, the consequences for human rights, biosphere integrity, and global climate will be severe. The policy implications are clear: the faster we reduce human emissions and draw down atmospheric CO2, the more of the permafrost domain we can save. Emissions reduction targets must be strengthened and accompanied by support for local peoples to protect intact ecological communities and natural carbon sinks within the permafrost domain. Some proposed geoengineering interventions such as solar shading, surface albedo modification, and vegetation manipulations are unproven and may exacerbate environmental injustice without providing lasting protection. Conversely, astounding advances in renewable energy have reopened viable pathways to halve human greenhouse gas emissions by 2030 and effectively stop them well before 2050. We call on leaders, corporations, researchers, and citizens everywhere to acknowledge the global importance of the permafrost domain and work towards climate restoration and empowerment of Indigenous and immigrant communities in these regions.

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“…The role of thermokarst lagoons for carbon turnover and greenhouse gas release have received little attention so far despite their role in coastal carbon dynamics (in 't Zandt et al 2020) and widespread occurrence along Arctic coasts (Angelopoulos et al 2021). Marine-water inundated systems may have the potential to effectively reduce CH 4 emissions through establishment of sulfate-reducing anaerobic methane oxidation (S-AOM).…”

Section: Introductionmentioning

confidence: 99%

Anaerobic methane oxidizing archaea offset sediment methane concentrations in Arctic thermokarst lagoons

Anthony

Jenrich

Zandt

et al. 2022

Preprint

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Thermokarst lagoons represent the transition state from a freshwater lacustrine to a marine environment, and receive little attention regarding their role for greenhouse gas production and release in Arctic permafrost landscapes. We studied the fate of methane (CH4) in sediments of a thermokarst lagoon in comparison to two thermokarst lakes on the Bykovsky Peninsula in northeastern Siberia through the analysis of sediment CH4 concentrations and isotopic signature, methane-cycling microbial taxa, sediment geochemistry, and lipid biomarkers. We specifically assessed whether sulfate-driven anaerobic methane oxidation (S-AOM) through anaerobic methanotrophic archaea (ANMEs), common in marine sediments with constant supply of sulfate and methane, establish after thermokarst lagoon development and whether sulfate-driven ANMEs consequently oxidize CH4 that would be emitted to the water column under thermokarst lake conditions. The marine-influenced lagoon environment had fundamentally different methane-cycling microbial communities and metabolic pathways compared to the freshwater lakes, suggesting a substantial reshaping of microbial and carbon dynamics during lagoon formation. Anaerobic sulfate-reducing ANME-2a/2b methanotrophs dominated the sulfate-rich sediments of the lagoon despite its known seasonal alternation between brackish and freshwater inflow. CH4 concentrations in the freshwater-influenced sediments averaged 1.34±0.98 μmol g-1, with highly depleted δ13C-CH4 values ranging from -89‰ to -70‰. In contrast, the sulfate-affected upper 300 cm of the lagoon exhibited low average CH4 concentrations of 0.011±0.005 μmol g-1 with comparatively enriched δ13C-CH4 values of -54‰ to -37‰ pointing to substantial methane oxidation. Non-competitive methylotrophic methanogens dominated the methanogenic community of the lakes and the lagoon, independent of porewater chemistry and depth. This potentially contributed to the high CH4 concentrations observed in all sulfate-poor sediments. Our study shows that S-AOM in lagoon sediments can effectively reduce sediment CH4 concentrations and we conclude that thermokarst lake to lagoon transitions have the potential to mitigate terrestrial methane fluxes before thermokarst lakes fully transition to a marine environment.

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Onshore Thermokarst Primes Subsea Permafrost Degradation

Cited by 13 publications

References 66 publications

Model Study of the Effects of Climate Change on the Methane Emissions on the Arctic Shelves

Model Study of the Effects of Climate Change on the Methane Emissions on the Arctic Shelves

We Must Stop Fossil Fuel Emissions to Protect Permafrost Ecosystems

Anaerobic methane oxidizing archaea offset sediment methane concentrations in Arctic thermokarst lagoons

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