Bacterial oxidation of methane within seeps in the northern Laptev Sea

2020 ◽  
Author(s):  
Anna Yurchenko ◽  
Elizaveta Krasnova ◽  
Igor Semiletov ◽  
Natal'ia Shakhova ◽  
Mikhail Spasennykh
Keyword(s):  
Stable Isotopes ◽  
Gas Hydrates ◽  
Arctic Shelf ◽  
Anaerobic Oxidation Of Methane ◽  
Laptev Sea ◽  
Sampling Station ◽  
Bacterial Oxidation ◽  
Oxidation Of Methane ◽  
Wide Range ◽  
Siberian Arctic

<p>Increase of methane concentration in atmosphere due to emission from Arctic shelf subsea deposits can play considerable role in climate change [1-2]. Methane seeps in East-Siberian and Laptev Seas were investigated in frames of complex research cruise АМК-78 onboard R/V «Akademik Mstislav Keldysh», (September 17 - October 22, 2019).</p><p>In the seep areas gas was collected to study its molecular and stable isotopes composition and reveal the genesis of discharging methane. Sediments were collected using box-corer for detailed lithological investigations and characterization of mineral inclusions. At the sampling station within methane seep in the Northern Laptev Sea, dark grey to black clays with hydrotroilite were collected.  They contained rounded inclusions of light grey carbonates with size up to 3x4cm.</p><p>Methane that migrates to the seafloor surface is characterized by wide range of stable isotopes composition values with predominance of <sup>13</sup>C depleted biogenic component [3-4].</p><p>Stable carbon and oxygen isotopes composition of carbonate inclusions was measured. The carbonates are strongly depleted in <sup>13</sup>C up to -32,4 ‰VPDB. δ<sup>18</sup>О varies in wide range between -3 and +4,4 ‰VPDB. Depletion of the carbonates in <sup>13</sup>C indicates its formation as a result of bacterial oxidation of methane in anaerobic conditions. Anaerobic oxidation of methane is an important biogeochemical process in the areas of methane emissions. The size and isotopes data of the authigenic methane-derived carbonates provide information on the intensity and time of methane discharge, geochemical characteristics of the fluids, including water. Enrichment of the carbonate inclusions in <sup>18</sup>O can be explained by the migration of isotopically heavy water from dissociating gas hydrates [5].</p><p>Obtained results of the complex study of discharging fluids and authigenic minerals allow to characterize the biochemogenic processes in seep sediments, local variations in the environmental conditions and methane flux and isotopic effects during bacterial oxidation of methane.</p><p> </p><p>Literature:</p><ol><li>Shakhova N., Semiletov I., Chuvilin E. Understanding the permafrost-hydrate system and associated methane releases in the East Siberian Arctic Shelf<strong> // </strong>Geosciences, 2019, 9, 251.</li> <li>Shakhova N.E., Sergienko V.I., Semiletov I.P. Contribution of East-Siberian shelf to the modern methane cycle // RAS bulletin, 2009, vol. 79, №6, pp. 507-518.</li> <li>Whiticar, M.J. Correlation of natural gases with their sources. In: Magoon, L., Dow, W. Eds., The Petroleum System — From Source to Trap. AAPG Memoir 60, 1994, pp. 261–284.</li> <li>Sapart, C. J., Shakhova, N., Semiletov, I., Jansen, J., Szidat, S., Kosmach, D., Dudarev, O., van der Veen, C., Egger, M., Sergienko, V.,; Salyuk, A., Tumskoy, V., Tison, J.L., Rockmann, T. The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis // Biogeosciences, 14, 9, 2283-2292, 2017.</li> <li>Bohrman G., Suess E., Greinert J., Teichert B., Naehr T. Has hydrate carbonates from Hydrate ridge, Cascadia convergent margin: indicators of near-seafloor clathrate deposits // Fourth Int. Conf. Gas Hydrates: Yokohama, Japan, 19023:102-107. 2002.</li> </ol>

scholarly journals Assessing the potential for non-turbulent methane escape from the East Siberian Arctic Shelf

2020 ◽  
Vol 17 (12) ◽  
pp. 3247-3275
Author(s):  
Matteo Puglini ◽  
Victor Brovkin ◽  
Pierre Regnier ◽  
Sandra Arndt
Keyword(s):  
Environmental Conditions ◽  
Transport Processes ◽  
Arctic Shelf ◽  
Delayed Response ◽  
Anaerobic Oxidation Of Methane ◽  
Laptev Sea ◽  
Ch4 Flux ◽  
Wide Range ◽  
Siberian Arctic ◽  
Methane Efflux

Abstract. The East Siberian Arctic Shelf (ESAS) hosts large yet poorly quantified reservoirs of subsea permafrost and associated gas hydrates. It has been suggested that the global-warming induced thawing and dissociation of these reservoirs is currently releasing methane (CH4) to the shallow coastal ocean and ultimately the atmosphere. However, a major unknown in assessing the contribution of this CH4 flux to the global CH4 cycle and its climate feedbacks is the fate of CH4 as it migrates towards the sediment–water interface. In marine sediments, (an)aerobic oxidation reactions generally act as a very efficient methane sink. However, a number of environmental conditions can reduce the efficiency of this biofilter. Here, we used a reaction-transport model to assess the efficiency of the benthic methane filter and, thus, the potential for benthic methane escape across a wide range of environmental conditions that could be encountered on the East Siberian Arctic Shelf. Results show that, under steady-state conditions, anaerobic oxidation of methane (AOM) acts as an efficient biofilter. However, high CH4 escape is simulated for rapidly accumulating and/or active sediments and can be further enhanced by the presence of organic matter with intermediate reactivity and/or intense local transport processes, such as bioirrigation. In addition, in active settings, the sudden onset of CH4 flux triggered by, for instance, permafrost thaw or hydrate destabilization can also drive a high non-turbulent methane escape of up to 19 µmol CH4 cm−2 yr−1 during a transient, multi-decadal period. This “window of opportunity” arises due to delayed response of the resident microbial community to suddenly changing CH4 fluxes. A first-order estimate of non-turbulent, benthic methane efflux from the Laptev Sea is derived as well. We find that, under present-day conditions, non-turbulent methane efflux from Laptev Sea sediments does not exceed 1 Gg CH4 yr−1. As a consequence, we conclude that previously published estimates of ocean–atmosphere CH4 fluxes from the ESAS cannot be supported by non-turbulent, benthic methane escape.

scholarly journals The Formation of Authigenic Carbonates at a Methane Seep Site in the Northern Part of the Laptev Sea

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 948
Author(s):  
Alexey Ruban ◽  
Maxim Rudmin ◽  
Oleg Dudarev ◽  
Alexey Mazurov
Keyword(s):  
Seawater Temperature ◽  
Cold Seep ◽  
Anaerobic Oxidation Of Methane ◽  
Laptev Sea ◽  
Cold Seeps ◽  
Authigenic Carbonates ◽  
Oxidation Of Methane ◽  
Major Oxide ◽  
Mg Content ◽  
The Laptev Sea

Authigenic carbonates from cold seeps are unique archives for studying environmental conditions, including biogeochemical processes associated with methane-rich fluid migration through the sediment column. The aim of this research was to study major oxide, mineralogical, and stable isotopic compositions of cold-seep authigenic carbonates collected in the northern part of the Laptev Sea. These carbonates are represented by Mg-calcite with an Mg content of 2% to 8%. The δ13C values range from −27.5‰ to −28.2‰ Vienna Peedee belemnite (VPDB) and indicate that carbonates formed due to anaerobic oxidation of methane, most likely thermogenic in origin. The authigenic pyrite in Mg-calcite is evidence of sulfate reduction during carbonate precipitation. The δ18O values of carbonates vary from 3.5‰ to 3.8‰ VPDB. The calculated δ18Ofluid values show that pore water temperature for precipitated Mg-calcite was comparable to bottom seawater temperature. The presence of authigenic carbonate in the upper horizons of sediments suggests that the sulfate–methane transition zone is shallowly below the sediment–water interface.

scholarly journals Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea

2017 ◽  
Vol 11 (5) ◽  
pp. 2305-2327 ◽  
Author(s):  
Alexander N. Charkin ◽  
Michiel Rutgers van der Loeff ◽  
Natalia E. Shakhova ◽  
Örjan Gustafsson ◽  
Oleg V. Dudarev ◽  
...  
Keyword(s):  
Submarine Groundwater Discharge ◽  
Water Discharge ◽  
Groundwater Discharge ◽  
Water Soluble ◽  
Arctic Shelf ◽  
The Arctic ◽  
Laptev Sea ◽  
Siberian Arctic ◽  
Submarine Groundwater ◽  
Shelf Seas

Abstract. It has been suggested that increasing terrestrial water discharge to the Arctic Ocean may partly occur as submarine groundwater discharge (SGD), yet there are no direct observations of this phenomenon in the Arctic shelf seas. This study tests the hypothesis that SGD does exist in the Siberian Arctic Shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The field-observational approach in the southeastern Laptev Sea used a combination of hydrological (temperature, salinity), geological (bottom sediment drilling, geoelectric surveys), and geochemical (224Ra, 223Ra, 228Ra, and 226Ra) techniques. Active SGD was documented in the vicinity of the Lena River delta with two different operational modes. In the first system, groundwater discharges through tectonogenic permafrost talik zones was registered in both winter and summer. The second SGD mechanism was cryogenic squeezing out of brine and water-soluble salts detected on the periphery of ice hummocks in the winter. The proposed mechanisms of groundwater transport and discharge in the Arctic land-shelf system is elaborated. Through salinity vs. 224Ra and 224Ra / 223Ra diagrams, the three main SGD-influenced water masses were identified and their end-member composition was constrained. Based on simple mass-balance box models, discharge rates at sites in the submarine permafrost talik zone were 1. 7 × 106 m3 d−1 or 19.9 m3 s−1, which is much higher than the April discharge of the Yana River. Further studies should apply these techniques on a broader scale with the objective of elucidating the relative importance of the SGD transport vector relative to surface freshwater discharge for both water balance and aquatic components such as dissolved organic carbon, carbon dioxide, methane, and nutrients.

scholarly journals Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea region

2012 ◽  
Vol 117 (F3) ◽  
pp. n/a-n/a ◽  
Author(s):  
D. J. Nicolsky ◽  
V. E. Romanovsky ◽  
N. N. Romanovskii ◽  
A. L. Kholodov ◽  
N. E. Shakhova ◽  
...  
Keyword(s):  
Arctic Shelf ◽  
Laptev Sea ◽  
Siberian Arctic ◽  
The Laptev Sea

scholarly journals The Impact of Methane Seepage on the Pore-Water Geochemistry across the East Siberian Arctic Shelf

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 397
Author(s):  
Natalia Guseva ◽  
Yulia Moiseeva ◽  
Darya Purgina ◽  
Elena Gershelis ◽  
Evgeniy Yakushev ◽  
...  
Keyword(s):  
Pore Water ◽  
World Ocean ◽  
Arctic Shelf ◽  
Anaerobic Oxidation Of Methane ◽  
Atmospheric Methane ◽  
Pore Waters ◽  
Geochemical Environment ◽  
Methane Seepage ◽  
Siberian Arctic ◽  
The Impact

East Siberian Arctic Shelf, the widest and the shallowest shelf of the World Ocean, covering greater than two million square kilometers, has recently been shown to be a significant modern source of atmospheric methane (CH4). The CH4 emitted to the water column could result from modern methanogenesis processes and/or could originate from seabed deposits (pre-formed CH4 preserved as free gas and/or gas hydrates). This paper focuses primarily on understanding the source and transformation of geofluid in the methane seepage areas using ions/trace elements and element ratios in the sediment pore-water. Six piston cores and totally 42 pore-water samples were collected in the East Siberian Sea and the Laptev Sea at water depths ranging from 22 to 68 m. In the active zones of methane release, concentrations of vanadium, thorium, phosphorus, aluminum are increased, while concentrations of cobalt, iron, manganese, uranium, molybdenum, copper are generally low. The behavior of these elements is determined by biogeochemical processes occurring in the pore-waters at the methane seeps sites (sulfate reduction, anaerobic oxidation of methane, secondary precipitation of carbonates and sulfides). These processes affect the geochemical environment and, consequently, the species of these elements within the pore-waters and the processes of their redistribution in the corresponding water–rock system.

scholarly journals Stratified Communities of Active Archaea in Deep Marine Subsurface Sediments

2006 ◽  
Vol 72 (7) ◽  
pp. 4596-4603 ◽  
Author(s):  
Ketil B. Sørensen ◽  
Andreas Teske
Keyword(s):  
16S Rrna ◽  
Sediment Surface ◽  
Anaerobic Oxidation Of Methane ◽  
Rt Pcr ◽  
Ocean Drilling Program ◽  
Clone Libraries ◽  
Oxidation Of Methane ◽  
Geochemical Properties ◽  
Wide Range ◽  
Subsurface Sediments

ABSTRACT Archaeal 16S rRNA was extracted from samples of deep marine subsurface sediments from Peru Margin site 1227, Ocean Drilling Program leg 201. The amounts of archaeal 16S rRNA in each extract were quantified by serial dilution and reverse transcription (RT)-PCR. The results indicated a 1,000-fold variation in rRNA content with depth in the sediment, with the highest concentrations found near the sediment surface and in the sulfate-methane transition zone (SMTZ). The phylogenetic composition of the active archaeal population revealed by cloning and sequencing of RT-PCR products changed with depth. Several phylotypes affiliated with marine benthic group B (MBGB) dominated clone libraries from the upper part of the SMTZ and were detected only in this layer. Members of the miscellaneous crenarchaeotal group (MCG) dominated clone libraries from the other layers. These results demonstrate that archaeal communities change in activity and community composition over short distances in geochemically distinct zones of deep subseafloor sediments and that these changes are traceable in the rRNA pool. It was shown for the first time that members of both the MCG and MBGB Archaea are more active in the SMTZ than in layers above and below. This indicates that they benefit either directly or indirectly from the anaerobic oxidation of methane. They also appear to be ecophysiologically flexible, as they have been retrieved from a wide range of marine sediments of various geochemical properties.

Sea-ice ploughmarks in the eastern Laptev Sea, East Siberian Arctic shelf

2016 ◽  
Vol 46 (1) ◽  
pp. 301-302 ◽  
Author(s):  
R. Ananyev ◽  
N. Dmitrevskiy ◽  
M. Jakobsson ◽  
L. Lobkovsky ◽  
S. Nikiforov ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Shelf ◽  
Laptev Sea ◽  
Siberian Arctic

scholarly journals Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf

2021 ◽  
Vol 118 (10) ◽  
pp. e2019672118
Author(s):  
Julia Steinbach ◽  
Henry Holmstrand ◽  
Kseniia Shcherbakova ◽  
Denis Kosmach ◽  
Volker Brüchert ◽  
...  
Keyword(s):  
Arctic Shelf ◽  
Laptev Sea ◽  
Methane Release ◽  
Horizontal Gradients ◽  
The Past ◽  
Gas Source ◽  
Stable Isotopic ◽  
Siberian Arctic ◽  
Subsea Permafrost ◽  
The Laptev Sea

The East Siberian Arctic Shelf holds large amounts of inundated carbon and methane (CH4). Holocene warming by overlying seawater, recently fortified by anthropogenic warming, has caused thawing of the underlying subsea permafrost. Despite extensive observations of elevated seawater CH4 in the past decades, relative contributions from different subsea compartments such as early diagenesis, subsea permafrost, methane hydrates, and underlying thermogenic/ free gas to these methane releases remain elusive. Dissolved methane concentrations observed in the Laptev Sea ranged from 3 to 1,500 nM (median 151 nM; oversaturation by ∼3,800%). Methane stable isotopic composition showed strong vertical and horizontal gradients with source signatures for two seepage areas of δ13C-CH4 = (−42.6 ± 0.5)/(−55.0 ± 0.5) ‰ and δD-CH4 = (−136.8 ± 8.0)/(−158.1 ± 5.5) ‰, suggesting a thermogenic/natural gas source. Increasingly enriched δ13C-CH4 and δD-CH4 at distance from the seeps indicated methane oxidation. The Δ14C-CH4 signal was strongly depleted (i.e., old) near the seeps (−993 ± 19/−1050 ± 89‰). Hence, all three isotope systems are consistent with methane release from an old, deep, and likely thermogenic pool to the outer Laptev Sea. This knowledge of what subsea sources are contributing to the observed methane release is a prerequisite to predictions on how these emissions will increase over coming decades and centuries.

scholarly journals Response of the Anaerobic Methanotroph “CandidatusMethanoperedens nitroreducens” to Oxygen Stress

2018 ◽  
Vol 84 (24) ◽  
Author(s):  
Simon Guerrero-Cruz ◽  
Geert Cremers ◽  
Theo A. van Alen ◽  
Huub J. M. Op den Camp ◽  
Mike S. M. Jetten ◽  
...  
Keyword(s):  
Nitrate Reduction ◽  
Enrichment Culture ◽  
Rrna Gene ◽  
Anaerobic Oxidation Of Methane ◽  
Cluster Assembly ◽  
Oxygen Exposure ◽  
Oxidation Of Methane ◽  
Wide Range ◽  
Genes Encoding ◽  
Metagenome Sequencing

ABSTRACT“CandidatusMethanoperedens nitroreducens” is an archaeon that couples the anaerobic oxidation of methane to nitrate reduction. In natural and man-made ecosystems, this archaeon is often found at oxic-anoxic interfaces where nitrate, the product of aerobic nitrification, cooccurs with methane produced by methanogens. As such, populations of “Ca. Methanoperedens nitroreducens” could be prone to regular oxygen exposure. Here, we investigated the effect of 5% (vol/vol) oxygen exposure in batch activity assays on a “Ca. Methanoperedens nitroreducens” culture, enriched from an Italian paddy field. Metagenome sequencing of the DNA extracted from the enrichment culture revealed that 83% of 16S rRNA gene reads were assigned to a novel strain, “CandidatusMethanoperedens nitroreducens Verserenetto.” RNA was extracted, and metatranscriptome sequencing upon oxygen exposure revealed that the active community changed, most notably in the appearance of aerobic methanotrophs. The gene expression of “Ca. Methanoperedens nitroreducens” revealed that the key genes encoding enzymes of the methane oxidation and nitrate reduction pathways were downregulated. In contrast to this, we identified upregulation of glutaredoxin, thioredoxin family/like proteins, rubrerythrins, peroxiredoxins, peroxidase, alkyl hydroperoxidase, type A flavoproteins, FeS cluster assembly protein, and cysteine desulfurases, indicating the genomic potential of “Ca. Methanoperedens nitroreducens Verserenetto” to counteract the oxidative damage and adapt in environments where they might be exposed to regular oxygen intrusion.IMPORTANCE“CandidatusMethanoperedens nitroreducens” is an anaerobic archaeon which couples the reduction of nitrate to the oxidation of methane. This microorganism is present in a wide range of aquatic environments and man-made ecosystems, such as paddy fields and wastewater treatment systems. In such environments, these archaea may experience regular oxygen exposure. However, “Ca. Methanoperedens nitroreducens” is able to thrive under such conditions and could be applied for the simultaneous removal of dissolved methane and nitrogenous pollutants in oxygen-limited systems. To understand what machinery “Ca. Methanoperedens nitroreducens” possesses to counteract the oxidative stress and survive, we characterized the response to oxygen exposure using a multi-omics approach.

Sign in / Sign up

Export Citation Format

Share Document