scholarly journals Fracture-controlled fluid transport supports microbial methane-oxidizing communities at Vestnesa Ridge

2019 ◽  
Vol 16 (10) ◽  
pp. 2221-2232 ◽  
Author(s):  
Haoyi Yao ◽  
Wei-Li Hong ◽  
Giuliana Panieri ◽  
Simone Sauer ◽  
Marta E. Torres ◽  
...  
Keyword(s):  
Fluid Transport ◽  
Surface Sediments ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Anaerobic Oxidation Of Methane ◽  
Gas Migration ◽  
Near Surface ◽  
Recent Onset ◽  
Oxidation Of Methane ◽  
Lipid Biomarker

Abstract. We report a rare observation of a mini-fracture in near-surface sediments (30 cm below the seafloor) visualized using a rotational scanning X-ray of a core recovered from the Lomvi pockmark, Vestnesa Ridge, west of Svalbard (1200 m water depth). Porewater geochemistry and lipid biomarker signatures revealed clear differences in the geochemical and biogeochemical regimes of this core compared with two additional unfractured cores recovered from pockmark sites at Vestnesa Ridge, which we attribute to differential methane transport mechanisms. In the sediment core featuring the shallow mini-fracture at pockmark Lomvi, we observed high concentrations of both methane and sulfate throughout the core in tandem with moderately elevated values for total alkalinity, 13C-depleted dissolved inorganic carbon (DIC), and 13C-depleted lipid biomarkers (diagnostic for the slow-growing microbial communities mediating the anaerobic oxidation of methane with sulfate – AOM). In a separate unfractured core, recovered from the same pockmark about 80 m away from the fractured core, we observed complete sulfate depletion in the top centimeters of the sediment and much more pronounced signatures of AOM than in the fractured core. Our data indicate a gas advection-dominated transport mode in both cores, facilitating methane migration into sulfate-rich surface sediments. However, the moderate expression of AOM signals suggest a rather recent onset of gas migration at the site of the fractured core, while the geochemical evidence for a well-established AOM community at the second coring site suggest that gas migration has been going on for a longer period of time. A third core recovered from another pockmark along the Vestnesa Ridge Lunde pockmark was dominated by diffusive transport with only weak geochemical and biogeochemical evidence for AOM. Our study highlights that advective fluid and gas transport supported by mini-fractures can be important in modulating methane dynamics in surface sediments.

scholarly journals Fracture-controlled fluid transport supports microbial methaneoxidizing communities at the Vestnesa Ridge

2018 ◽  
Author(s):  
Haoyi Yao ◽  
Wei-Li Hong ◽  
Giuliana Panieri ◽  
Simone Sauer ◽  
Marta E. Torres ◽  
...  
Keyword(s):  
Fluid Transport ◽  
Surface Sediments ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Anaerobic Oxidation Of Methane ◽  
Gas Migration ◽  
Near Surface ◽  
Recent Onset ◽  
Oxidation Of Methane ◽  
Lipid Biomarker

Abstract. We report on a rare observation of a mini-fracture in near-surface sediments (30 cm below the seafloor) visualized using rotational scanning X-ray of a core recovered from the Lomvi pockmark, Vestnesa Ridge west of Svalbard (1200 m water depth). Porewater geochemistry and lipid biomarker signatures revealed clear differences in the geochemical and biogeochemical regimes of this core compared with two additional ones recovered from pockmarks sites at Vestnesa Ridge, which we attribute to differential methane transport mechanisms. In the sediments core featuring the shallow mini-fracture at pockmark Lomvi, we observed high concentrations of both methane and sulfate throughout the core in tandem with moderately elevated values for total alkalinity, 13C-depleted dissolved inorganic carbon (DIC), and 13C-depleted lipid biomarkers (diagnostic for the slow-growing microbial communities mediating the anaerobic oxidation of methane with sulfate – AOM). In another core recovered from the same pockmark about 80 m away from the fractured core, we observed complete sulfate depletion in the top centimeters of the sediment and much more pronounced signatures of AOM than in the fractured core. Our data indicate a gas advection-dominated transport mode in both cores facilitating methane migration into sulfate-rich surface sediments. However, the more moderate expression of AOM signals suggest a rather recent onset of gas migration at the site of the fractured core, while the geochemical evidence for a well-established AOM community at the second coring site at the Lomvi pockmark suggest that gas migration has been going on for a longer period of time. A third core recovered from Lunde pockmark was dominated by diffusive transport with only weak geochemical and biogeochemical evidence for AOM. Our study highlights that advective fluid and gas transport supported by mini-fractures can be important in modulating methane dynamics in surface sediments.

scholarly journals Biogeochemical and microbiological evidence for methane-related archaeal communities at active submarine mud volcanoes on the Canadian Beaufort Sea slope

2018 ◽  
Author(s):  
Dong-Hun Lee ◽  
Jung-Hyun Kim ◽  
Yung Mi Lee ◽  
Alina Stadnitskaia ◽  
Young Keun Jin ◽  
...  
Keyword(s):  
16S Rrna ◽  
Surface Sediments ◽  
Beaufort Sea ◽  
Lipid Biomarkers ◽  
Anaerobic Oxidation Of Methane ◽  
Mud Volcanoes ◽  
Δ13c Values ◽  
Oxidation Of Methane ◽  
Lipid Biomarker ◽  
Archaeal Communities

Abstract. In this study, we report lipid biomarker patterns and phylogenetic identities of key microbes mediating anaerobic oxidation of methane (AOM) communities in active mud volcanos (MVs) on the continental slope of the Canadian Beaufort Sea. The enriched δ13C values of total organic carbon (TOC) as well as lipid biomarkers such as archaeol and biphytanes (BPs) relative to δ13CCH4 values suggested that the contribution of AOM-related biomass to sedimentary TOC was in general negligible in the Beaufort Sea MVs investigated. However, the δ13C values of sn-2- and sn-3-hydroxyarchaeol were more negative than CH4, indicating the presence of AOM communities, albeit in a small amount. The ratio of sn-2-hydroxyarchaeol to archaeol and the 16S rRNA results indeed indicated that archaea of the ANME-2c and ANME-3 clades were involved in AOM. Further studies are needed to investigate the diversity and distribution of AOM communities and to characterize their habitats in the uppermost surface sediments of Beaufort Sea MV systems.

Carbonate formation by anaerobic oxidation of methane: Evidence from lipid biomarker and fossil 16S rDNA

2008 ◽  
Vol 72 (7) ◽  
pp. 1824-1836 ◽  
Author(s):  
A. Stadnitskaia ◽  
D. Nadezhkin ◽  
B. Abbas ◽  
V. Blinova ◽  
M.K. Ivanov ◽  
...  
Keyword(s):  
16S Rdna ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Oxidation Of Methane ◽  
Carbonate Formation ◽  
Lipid Biomarker

scholarly journals Seasonal Mixing and Biological Controls of the Carbonate System in a River-Dominated Continental Shelf Subject to Eutrophication and Hypoxia in the Northern Gulf of Mexico

2021 ◽  
Vol 8 ◽  
Author(s):  
Wei-Jen Huang ◽  
Wei-Jun Cai ◽  
Xinping Hu
Keyword(s):  
Gulf Of Mexico ◽  
Continental Shelf ◽  
Dissolved Inorganic Carbon ◽  
Time Lag ◽  
Distribution Patterns ◽  
Detailed Examination ◽  
Total Alkalinity ◽  
Dominant Factor ◽  
Near Surface ◽  
Northern Gulf Of Mexico

Large rivers export a large amount of dissolved inorganic carbon (DIC) and nutrients to continental shelves; and subsequent river-to-sea mixing, eutrophication, and seasonal hypoxia (dissolved oxygen < 2 mg⋅L–1) can further modify DIC and nutrient distributions and fluxes. However, quantitative studies of seasonal carbonate variations on shelves are still insufficient. We collected total alkalinity (TA), DIC, and NO3– data from nine cruises conducted between 2006 and 2010 on the northern Gulf of Mexico continental shelf, an area strongly influenced by the Mississippi and Atchafalaya Rivers. We applied a three-end-member model (based on salinity and potential alkalinity) to our data to remove the contribution of physical mixing to DIC and nitrate distribution patterns and to derive the net in situ removal of DIC and nitrate (ΔDIC and ΔNO3–, respectively). Systematic analyses demonstrated that the seasonal net DIC removal in the near-surface water was strong during summer and weak in winter. The peak in net DIC production in the near-bottom, subsurface waters of the inner and middle sections of the shelf occurred between July and September; it was coupled, but with a time lag, to the peak in the net DIC removal that occurred in the near-surface waters in June. A similar 2-month delay (i.e., January vs. November) could also be observed between their minima. A detailed examination of the relationship between ΔDIC and ΔNO3– demonstrates that net biological activity was the dominant factor of DIC removal and addition. Other effects, such as air–sea CO2 gas exchange, wetland exports, CaCO3 precipitation, and a regional variation of the Redfield ratio, were relatively minor. We suggest that the delayed coupling between eutrophic surface and hypoxic bottom waters reported here may also be seen in the carbon and nutrient cycles of other nutrient-rich, river-dominated ocean margins worldwide.

scholarly journals Microbial Alkalinity Production and Silicate Alteration in Methane Charged Marine Sediments: Implications for Porewater Chemistry and Diagenetic Carbonate Formation

2022 ◽  
Vol 9 ◽  
Author(s):  
Patrick Meister ◽  
Gerhard Herda ◽  
Elena Petrishcheva ◽  
Susanne Gier ◽  
Gerald R. Dickens ◽  
...  
Keyword(s):  
Transport Model ◽  
Total Alkalinity ◽  
Anaerobic Oxidation Of Methane ◽  
Deep Biosphere ◽  
Ocean Drilling Program ◽  
Oxidation Of Methane ◽  
Carbonate Formation ◽  
Reaction Transport ◽  
The Stability ◽  
Fundamental Insight

A numerical reaction-transport model was developed to simulate the effects of microbial activity and mineral reactions on the composition of porewater in a 230-m-thick Pleistocene interval drilled in the Peru-Chile Trench (Ocean Drilling Program, Site 1230). This site has porewater profiles similar to those along many continental margins, where intense methanogenesis occurs and alkalinity surpasses 100 mmol/L. Simulations show that microbial sulphate reduction, anaerobic oxidation of methane, and ammonium release from organic matter degradation only account for parts of total alkalinity, and excess CO2 produced during methanogenesis leads to acidification of porewater. Additional alkalinity is produced by slow alteration of primary aluminosilicate minerals to kaolinite and SiO2. Overall, alkalinity production in the methanogenic zone is sufficient to prevent dissolution of carbonate minerals; indeed, it contributes to the formation of cemented carbonate layers at a supersaturation front near the sulphate-methane transition zone. Within the methanogenic zone, carbonate formation is largely inhibited by cation diffusion but occurs rapidly if cations are transported into the zone via fluid conduits, such as faults. The simulation presented here provides fundamental insight into the diagenetic effects of the deep biosphere and may also be applicable for the long-term prediction of the stability and safety of deep CO2 storage reservoirs.

scholarly journals ANME-2d anaerobic methanotrophic archaea differ from other ANME archaea in lipid composition and carbon source

2019 ◽  
Author(s):  
Julia M. Kurth ◽  
Nadine T. Smit ◽  
Stefanie Berger ◽  
Stefan Schouten ◽  
Mike S.M. Jetten ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lipid Composition ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Freshwater Ecosystems ◽  
Anaerobic Oxidation Of Methane ◽  
Marine Environments ◽  
Sulfate Reducing ◽  
Oxidation Of Methane ◽  
Main Carbon Source

AbstractThe anaerobic oxidation of methane (AOM) is a microbial process present in marine and freshwater environments. AOM is important for reducing the emission of the second most important greenhouse gas methane. In marine environments anaerobic methanotrophic archaea (ANME) are involved in sulfate-reducing AOM. In contrast,Ca. Methanoperedens of the ANME-2d cluster carries out nitrate AOM in freshwater ecosystems. Despite the importance of those organisms for AOM in non-marine environments not much is known about their lipid composition or carbon sources. To close this gap, we analyzed the lipid composition of ANME-2d archaea and found that they mainly synthesize archaeol and hydroxyarchaeol as well as different (hydroxy-) glycerol dialkyl glycerol tetraethers, albeit in much lower amounts. Abundant lipid headgroups were dihexose, monomethyl-phosphatidyl ethanolamine and phosphatidyl hexose. Moreover, a monopentose was detected as a lipid headgroup which is rare among microorganisms. Batch incubations with13C labelled bicarbonate and methane showed that methane is the main carbon source of ANME-2d archaea varying from ANME-1 archaea which primarily assimilate dissolved inorganic carbon (DIC). ANME-2d archaea also assimilate DIC, but to a lower extent than methane. The lipid characterization and analysis of the carbon source ofCa.Methanoperedens facilitates distinction between ANME-2d and other ANMEs.

scholarly journals Anaerobic methanotrophic archaea of the ANME-2d clade feature lipid composition that differs from other ANME archaea

2019 ◽  
Vol 95 (7) ◽  
Author(s):  
Julia M Kurth ◽  
Nadine T Smit ◽  
Stefanie Berger ◽  
Stefan Schouten ◽  
Mike S M Jetten ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lipid Composition ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Freshwater Ecosystems ◽  
Anaerobic Oxidation Of Methane ◽  
Marine Environments ◽  
Sulfate Reducing ◽  
Oxidation Of Methane ◽  
Main Carbon Source

ABSTRACTThe anaerobic oxidation of methane (AOM) is a microbial process present in marine and freshwater environments. AOM is important for reducing the emission of the second most important greenhouse gas methane. In marine environments anaerobic methanotrophic archaea (ANME) are involved in sulfate-reducing AOM. In contrast, Ca. Methanoperedens of the ANME-2d cluster carries out nitrate AOM in freshwater ecosystems. Despite the importance of those organisms for AOM in non-marine environments little is known about their lipid composition or carbon sources. To close this gap, we analysed the lipid composition of ANME-2d archaea and found that they mainly synthesise archaeol and hydroxyarchaeol as well as different (hydroxy-) glycerol dialkyl glycerol tetraethers, albeit in much lower amounts. Abundant lipid headgroups were dihexose, monomethyl-phosphatidyl ethanolamine and phosphatidyl hexose. Moreover, a monopentose was detected as a lipid headgroup that is rare among microorganisms. Batch incubations with 13C labelled bicarbonate and methane showed that methane is the main carbon source of ANME-2d archaea varying from ANME-1 archaea that primarily assimilate dissolved inorganic carbon (DIC). ANME-2d archaea also assimilate DIC, but to a lower extent than methane. The lipid characterisation and analysis of the carbon source of Ca. Methanoperedens facilitates distinction between ANME-2d and other ANMEs.

scholarly journals Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica

2009 ◽  
Vol 6 (3) ◽  
pp. 5741-5769 ◽  
Author(s):  
H. Niemann ◽  
D. Fischer ◽  
D. Graffe ◽  
K. Knittel ◽  
A. Montiel ◽  
...  
Keyword(s):  
Surface Sediments ◽  
Sediment Cores ◽  
Weddell Sea ◽  
Cold Seep ◽  
Anaerobic Oxidation Of Methane ◽  
Ice Shelf ◽  
Sediment Depth ◽  
Oxidation Of Methane ◽  
Low Activity ◽  
Thermogenic Methane

Abstract. First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005). Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and further videographical examinations. During two dives with ROV Cherokee (MARUM, Bremen), several bivalve shell agglomerations of the seep-associated, chemo syntheticclam Calyptogena sp. were found in the trough of the Crane and Evans glacier. The absence of living clam specimens indicates that the flux of sulphide and hence the seepage activity is diminished at present. This impression was further substantiated by our geochemical observations. Concentrations of thermogenic methane were moderately elevated with 2 μM in surface sediments of a clam patch, increasing up to 9 μM at a sediment depth of about 1 m in the bottom sections of the sediment cores. This correlated with a moderate decrease in sulphate from 28 mM at the surface down to 23.4 mM, an increase in sulphide to up to 1.43 mM and elevated rates of the anaerobic oxidation of methane (AOM) of up to 600 pmol cm−3 d−1 at about 1 m below the seafloor. Molecular analyses indicate that methanotrophic archaea related to ANME-3 are the most likely candidates mediating AOM in sediments of the Larsen B seep (Domack et al., 2005; EOS 86, 269–276).

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