Dynamic and history of methane seepage in the SW Barents Sea: new insights from Leirdjupet Fault Complex

Argentino, Claudio; Waghorn, Kate Alyse; Vadakkepuliyambatta, Sunil; Polteau, S.; Bünz, Stefan; Panieri, Giuliana

doi:10.1038/s41598-021-83542-0

Cited by 24 publications

(30 citation statements)

References 80 publications

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“…Such conditions have been reported from many modern cold seeps from gas hydrate bearing areas, e.g. Cascadia Margin (Bohrmann et al, 1998(Bohrmann et al, , 2002Greinert et al, 2013), Gulf of Cadiz (Magalhães et al, 2012), Gulf of Mexico (Roberts and Feng, 2013), Congo Fan (Feng et al, 2010a), Barents Sea (Crémière et al, 2016;Argentino et al, 2021;Yao et al, 2021); the δ 18 O proxy has been applied to fossil seep carbonates as well (Pierre and Rouchy, 2004;Campbell, 2006;Campbell et al, 2008;Argentino et al, 2019;Bojanowski et al, 2021). Owing to their microbial origin, seep carbonates incorporate and harbor typical communities of methane-oxidizing archaea and sulfate-reducing bacteria (Marlow et al, 2014).…”

Section: Introductionmentioning

confidence: 64%

Biogeochemistry and timing of methane-derived carbonate formation at Leirdjupet fault complex, SW Barents sea

et al. 2022

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The origin of modern seafloor methane emissions in the Barents Sea is tightly connected to the glacio-tectonic and oceanographic transformations following the last ice age. Those regional events induced geological structure re-activation and destabilization of gas hydrate reservoirs over large areas of the European continental margins, sustaining widespread fluid plumbing systems. Despite the increasing number of new active seep discoveries, their accurate geochronology and paleo-dynamic is still poorly resolved, thus hindering precise identification of triggering factors and mechanisms controlling past and future seafloor emissions. Here, we report the distribution, petrographic (thin section, electron backscatter diffraction), isotopic (δ13C, δ18O) and lipid biomarker composition of methane-derived carbonates collected from Leirdjupet Fault Complex, SW Barents Sea, at 300 m depth during an ROV survey in 2021. Carbonates are located inside a 120 x 220 m elongated pockmark and form <10 m2 bodies protruding for about 2 m above the adjacent seafloor. Microstructural analyses of vein-filling cements showed the occurrence of three–five generations of isopachous aragonitic cement separated by dissolution surfaces indicative of intermittent oxidizing conditions. The integration of phase-specific isotopic analysis and U/Th dating showed δ13C values between −28.6‰ to −10.1‰ and δ18O between 4.6‰ and 5.3‰, enabling us to track carbonate mineral precipitation over the last ∼8 ka. Lipid biomarkers and their compound-specific δ13C analysis in the bulk carbonate revealed the presence of anaerobic methanotrophic archaea of the ANME-2 clade associated with sulfate-reducing bacteria of the Seep-SRB1 clade, as well as traces of petroleum. Our results indicate that methane and petroleum seepage in this area followed a similar evolution as in other southernmost Barents Sea sites controlled by the asynchronous deglaciation of the Barents Sea shelf, and that methane-derived carbonate precipitation is still an active process at many Arctic locations.

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Section: Introductionmentioning

confidence: 64%

Biogeochemistry and timing of methane-derived carbonate formation at Leirdjupet fault complex, SW Barents sea

et al. 2022

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“…On the contrary, the rates of microbial biogeochemical processes increases manifold in sediments in sites of methane release such as mud volcanoes and methane seeps. The composition of microbial communities of sediments in places where methane is released to the seafloor is also very different from background areas [21][22][23][24]. Our results show that methane concentrations and rates of microbial processes in sediments in the northern part of the Barents Sea were noticeably higher than in oligotrophic areas of the Laptev Sea, but they were orders of magnitude lower than in the methane seep areas in the Laptev Sea and in the Haakon Mosby Mud Volcano zone (Table 4).…”

Section: Microbial Processes Of Transformation Of Organic Matter In Sediments Of the Arctic Seas: The Role Of Methanementioning

confidence: 55%

“…The study of the processes of the methane cycle carried out under strictly anoxic (methanogenesis and anaerobic oxidation of methane) and under oxic (aerobic oxidation of methane) conditions, as well as the study of microbial processes at the border of oxic and anoxic zones of sediments in the Barents Sea provide new insights into the methane cycle in marine sediments. Most of studies dedicated to the methane cycling in the Barents Sea were focused on methane-rich sites, such as methane seeps and mud volcanoes [20][21][22][23]. Particularly, analysis of microbial processes at the Haakon Mosby Mud Volcano revealed that the high methane availability and different fluid flow regimens provide distinct niches for aerobic (Methylobacter and Methylophaga) and anaerobic (mostly ANME-3 lineage) methanotrophs [22].…”

Section: Introductionmentioning

confidence: 99%

Microbial Communities Involved in Methane, Sulfur, and Nitrogen Cycling in the Sediments of the Barents Sea

et al. 2021

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A combination of physicochemical and radiotracer analysis, high-throughput sequencing of the 16S rRNA, and particulate methane monooxygenase subunit A (pmoA) genes was used to link a microbial community profile with methane, sulfur, and nitrogen cycling processes. The objects of study were surface sediments sampled at five stations in the northern part of the Barents Sea. The methane content in the upper layers (0–5 cm) ranged from 0.2 to 2.4 µM and increased with depth (16–19 cm) to 9.5 µM. The rate of methane oxidation in the oxic upper layers varied from 2 to 23 nmol CH4 L−1 day−1 and decreased to 0.3 nmol L−1 day−1 in the anoxic zone at a depth of 16–19 cm. Sulfate reduction rates were much higher, from 0.3 to 2.8 µmol L−1 day−1. In the surface sediments, ammonia-oxidizing Nitrosopumilaceae were abundant; the subsequent oxidation of nitrite to nitrate can be carried out by Nitrospira sp. Aerobic methane oxidation could be performed by uncultured deep-sea cluster 3 of gamma-proteobacterial methanotrophs. Undetectable low levels of methanogenesis were consistent with a near complete absence of methanogens. Anaerobic methane oxidation in the deeper sediments was likely performed by ANME-2a-2b and ANME-2c archaea in consortium with sulfate-reducing Desulfobacterota. Sulfide can be oxidized by nitrate-reducing Sulfurovum sp. Thus, the sulfur cycle was linked with the anaerobic oxidation of methane and the nitrogen cycle, which included the oxidation of ammonium to nitrate in the oxic zone and denitrification coupled to the oxidation of sulfide in the deeper sediments. Methane concentrations and rates of microbial biogeochemical processes in sediments in the northern part of the Barents Sea were noticeably higher than in oligotrophic areas of the Arctic Ocean, indicating that an increase in methane concentration significantly activates microbial processes.

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“…Stable isotopes of C and O, petrography, and the mineralogy of methane-derived authigenic carbonates (MDAC) in the Arctic seas have been examined in several studies (Pauly, 1963;Schubert et al, 1997;Lein et al, 1999;Kravchishina et al, 2017;Savvichev et al, 2018a, etc.). MDAC were found as Mg-calcite cement and pavement-forming crusts at the sediment-water interface of various high latitudinal seas, such as in the North Sea at depths of 120-300 m (Crémière et al, 2016b;Mazzini et al, 2016), in the Norwegian Sea at 220 m (Sauer et al, 2017), and in the Barents Sea at 220-400 m (Crémière et al, 2016a;Hong et al, 2017;Argentino et al, 2021). They were also observed in other climatic zones, such as the Green Canyon in the northern Gulf of Mexico (Bian et al, 2013).…”

Section: Introductionmentioning

confidence: 94%

Methane-Derived Authigenic Carbonates on the Seafloor of the Laptev Sea Shelf

et al. 2021

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Seafloor authigenic carbonate crusts are widespread in various oceanic and marine settings, excluding high-latitude basins that are corrosive to carbonate precipitation. Newly formed carbonate formations are relatively rare in modern Arctic marine sediments. Although the first-order principles of seep carbonate formation are currently quite well constrained, little is known regarding the duration or mode of carbonate formation in the Siberian Arctic shelf. Large (massive slabs or blocks) and small crusts that were micrite cemented have been recently discovered on the seafloor of the Siberian Arctic seas within the area of known seep activity in the outer Laptev Sea shelf. Cold methane seeps were detected in the area due to the presence of an acoustic anomaly in the water column (gas flares). Microbial mats, methane gas bubbles, and carbonate crusts were observed using a towed camera platform. Here, we report new geochemical and mineralogical data on authigenic shallow Siberian Arctic cold-seep carbonate crusts to elucidate its genesis. The Laptev Sea carbonate crusts mainly consist of high-Mg calcite (up to 23 mol % MgCO3). The δ13C values in carbonates range significantly (from –40.1 to –25.9‰ VPDB), while the δ18O values vary in a narrow range (+4.4 ± 0.2‰ VPDB). The δ13C values of Corg that was determined from carbonates range from –40.2 to –31.1‰ VPDB. Using the isotope data and taking into account the geological setting, we consider that not only microbial but possibly thermogenic methane participated in the authigenic carbonate precipitation. Carbonate crust formation occurred below the water/sediment interface of the shallow Siberian Arctic shelf as a result of gas hydrate dissociation during Holocene warming events. The studied carbonate crusts were exhumated after precipitation into shallow subsurface shelf sediments.

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Dynamic and history of methane seepage in the SW Barents Sea: new insights from Leirdjupet Fault Complex

Cited by 24 publications

References 80 publications

Biogeochemistry and timing of methane-derived carbonate formation at Leirdjupet fault complex, SW Barents sea

Biogeochemistry and timing of methane-derived carbonate formation at Leirdjupet fault complex, SW Barents sea

Microbial Communities Involved in Methane, Sulfur, and Nitrogen Cycling in the Sediments of the Barents Sea

Methane-Derived Authigenic Carbonates on the Seafloor of the Laptev Sea Shelf

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