Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor

Andreassen, Karin; Hubbard, Alun; Winsborrow, Monica; Patton, Henry; Vadakkepuliyambatta, Sunil; Plaza‐Faverola, Andreia; Gudlaugsson, Eythor; Serov, Pavel; Deryabin, Alexey; Mattingsdal, Rune; Mienert, Jürgen; Bünz, Stefan

doi:10.1126/science.aal4500

Cited by 207 publications

(213 citation statements)

References 60 publications

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“…Seepage at the Shelf-Area has been attributed to hydrate dissociation triggered by ice sheet unloading after the last deglaciation, with the present-day seepage locations marking previous GHSZ pinch-out locations (Portnov et al, 2016). This hypothesis is supported by similar evidence from the formerly glaciated continental margin of the Barents Sea (Andreassen et al, 2017). Earthquakes related to extension of the nearby spreading ridge system ( Figure 1) may influence bubble seepage indirectly (Plaza-Faverola et al, 2015).…”

Section: Citationmentioning

confidence: 76%

Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard

Veloso

Jansson

Batist

et al. 2019

Geophysical Research Letters

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Large reservoirs of methane present in Arctic marine sediments are susceptible to rapid warming, promoting increasing methane emissions. Gas bubbles in the water column can be detected, and flow rates can be quantified using hydroacoustic survey methods, making it possible to monitor spatiotemporal variability. We present methane (CH4) bubble flow rates derived from hydroacoustic data sets acquired during 11 research expeditions to the western Svalbard continental margin (2008–2014). Three seepage areas emit in total 725–1,125 t CH4/year, and bubble fluxes are up to 2 kg·m−2·year−1. Bubble fluxes vary between different surveys, but no clear trend can be identified. Flux variability analyses suggest that two areas are geologically interconnected, displaying alternating flow changes. Spatial migration of bubble seepage was observed to follow seasonal changes in the theoretical landward limit of the hydrate stability zone, suggesting that formation/dissociation of shallow hydrates, modulated by bottom water temperatures, influences seafloor bubble release.

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Section: Citationmentioning

confidence: 76%

Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard

Veloso

Jansson

Batist

et al. 2019

Geophysical Research Letters

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“…This mechanism may be present even at depths exceeding 1,000 m, particularly if gas plumes are strong and extend high into the water column (D'souza et al, ; Leifer et al, ). It is feasible that this upwelling effect of nutrient‐rich water, and therefore an enhancement of photosynthetic primary production, also occurs at the crater area where the water depth is only 370 m and intense gas seepage with CH 4 bubble streams up to 200 m height were observed (Andreassen et al, ).…”

Section: Discussionmentioning

confidence: 99%

Development, Productivity, and Seasonality of Living Planktonic Foraminiferal Faunas and Limacina helicina in an Area of Intense Methane Seepage in the Barents Sea

et al. 2020

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Although the plankton communities in the Barents Sea have been intensely studied for decades, little is known about the living planktonic foraminiferal (LPF) and pteropod faunas, especially those found at methane seep sites. Along a repeated transect in the “crater area” (northern Barents Sea, 74.9°N, 27.7°E) in spring and summer 2016 the flux of LPF and of the pteropod species Limacina helicina showed a high degree of variability. The LPF had low concentration (0–6 individuals m−3) and small tests (x̄ = 103.3 μm) in spring and a 53‐fold increase (43–436 individuals m−3) and larger tests (x̄ = 188.6 μm) in summer. Similarly, the concentration of L. helicina showed a tenfold increase between spring and summer. The LPF species composition remained stable with the exception of the appearance of subtropical species in summer. No relationship was observed between the spatial distribution of LPF, L. helicina, and methane concentrations in the area. The methane plumes in April coincided with elevated dissolved inorganic carbon, low pH, and calcium carbonate saturation states, and the methane concentration seemed to be controlled by lateral advection. The δ13C and δ18O of Neogloboquadrina pachyderma and Turborotalita quinqueloba are comparable to previous observations in the Arctic and do not show any influence of methane in the isotopic signals of the shells. Although no evidence of direct impact of high methane concentrations on the LPF (size and concentration) were found, we speculate that methane could indirectly enhance primary productivity, and thus biomass, through several potential pathways.

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“…Alternatively, dissociation of clathrate hydrates (methane [CH 4 · n H 2 O] or CO 2 [CO 2 · n H 2 O]) could perhaps trigger an energetic release of volatiles. On Earth, violent gas blowouts have created craters with raised ejecta rims on the Yamal peninsula in Russia (e.g., Buldovich et al, ; Leibman et al, ), and subaqueous craters in the Arctic were formed by massive release of methane from destabilized gas hydrates (Andreassen et al, ). Methane has been detected in the Martian atmosphere (Webster et al, ), and may have been present in the past as well.…”

Section: Discussionmentioning

confidence: 99%

Grid Mapping the Northern Plains of Mars: A New Overview of Recent Water‐ and Ice‐Related Landforms in Acidalia Planitia

et al. 2019

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We used a grid‐mapping technique to analyze the distribution of 13 water‐ and ice‐related landforms in Acidalia Planitia as part of a joint effort to study the three main basins in the northern lowlands of Mars, that is, Acidalia, Utopia, and Arcadia Planitiae. The landforms were mapped at full Context Camera resolution along a 300‐km‐wide strip from 20°N to 84°N. We identified four landform assemblages: (1) Geologically recent polar cap (massive ice), which superposes the latitude‐dependent mantle (LDM) (LA1); (2) ice‐related landforms, such as LDM, textured terrain, small‐scale polygons, scalloped terrain, large‐scale viscous flow features, and gullies, which have an overlapping distribution (LA2); (3) surface features possibly related to water and subsurface sediment mobilization (LA3; kilometer‐scale polygons, large pitted mounds, small pitted mounds, thumbprint terrain); and (4) irregularly shaped pits with raised rims on equator‐facing slopes. Pits are likely the result of an energetic release of volatiles (H2O, CO2, and CH4), rather than impact‐, volcanism‐, or wind‐related processes. LDM occurs ubiquitously from 44°N to 78°N in Acidalia Planitia. Various observations suggest an origin of air fall deposition of LDM, which contains less ice in the uppermost tens of meters in Acidalia Planitia than in Arcadia and Utopia Planitiae. However, LDM may be thicker and more extended in the past in Acidalia Planitia. The transition between LDM‐free terrain and LDM is situated further north than in Utopia and Arcadia Planitiae, suggesting different past and/or present climatic conditions among the main basins in the northern lowlands.

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Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor

Cited by 207 publications

References 60 publications

Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard

Variability of Acoustically Evidenced Methane Bubble Emissions Offshore Western Svalbard

Development, Productivity, and Seasonality of Living Planktonic Foraminiferal Faunas and Limacina helicina in an Area of Intense Methane Seepage in the Barents Sea

Grid Mapping the Northern Plains of Mars: A New Overview of Recent Water‐ and Ice‐Related Landforms in Acidalia Planitia

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