Anaerobic methane oxidation rates at the sulfate‐methane transition in marine sediments from Kattegat and Skagerrak (Denmark)1

Iversen, Niels; Jørgensen, Bo Barker

doi:10.4319/lo.1985.30.5.0944

Cited by 510 publications

(297 citation statements)

References 42 publications

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“…In marine sediments, anaerobic methane oxidation is the dominant pathway for methane consumption (Blair and Aller, 1995;Borowski et al, 1996;Burns, 1998;Iverson and Jørgensen, 1985;Reeburgh, 1980), and consequently, the flux of methane to the atmosphere from marine sediments is small compared to other sources (Reeburgh, 1996). However, it is unclear whether this has always been true or if this process can be disrupted by future climate change, and thus, it is important to understand the mechanism of anaerobic methane oxidation.…”

Section: Introductionmentioning

confidence: 99%

Archaeal lipids in Mediterranean cold seeps: molecular proxies for anaerobic methane oxidation

Pancost

Hopmans

Damsté

2001

Geochimica et Cosmochimica Acta

266

175

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Abstract-We investigated the distributions and ␦ 13 C values of biomarkers for Archaea associated with anaerobic methane oxidation in disparate settings throughout two Eastern Mediterranean mud dome fields. All major classes of archaeal lipids are present in the studied sediments, including isoprenoid glycerol diethers, isoprenoid glycerol dialkyl glycerol tetraethers, and irregular isoprenoid hydrocarbons. Of the compounds present, many, including a novel glycerol tetraether and sn-3-hydroxyarchaeol, have not been previously reported for settings in which methane oxidation is presumed to occur. Archaeal lipids are depleted in 13 C, indicating that the Archaea from which they derive are either directly or indirectly involved with methane consumption. The most widespread archaeal lipids are archaeol, PMI, and glycerol tetraethers, and these compounds are present at all active sites. However, archaeal lipid abundances and distributions are highly variable; ratios of crocetane, PMI, and hydroxyarchaeol relative to archaeol vary from 0 to 6.5, from 0 to 2, and from 0 to 1, respectively. These results suggest that archaeal communities differ amongst the sites examined. In addition, carbon isotopic variability amongst archaeal biomarkers in a given mud breccia can be as large as 24 ‰, suggesting that even at single sites multiple archaeal species perform or are supported by anaerobic methane oxidation.

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Section: Introductionmentioning

confidence: 99%

Archaeal lipids in Mediterranean cold seeps: molecular proxies for anaerobic methane oxidation

Pancost

Hopmans

Damsté

2001

Geochimica et Cosmochimica Acta

266

175

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“…While AOM is thus generally coupled to SO 4 2À reduction (SDMO) in marine waters and sediments (e.g. Iversen and Jørgensen, 1985;Boetius et al, 2000;Jørgensen et al, 2001), other electron acceptors of AOM have been much less frequently studied in freshwater systems. Due to low the SO 4 2À concentrations usually observed in freshwaters environments, AOM is often considered to be negligible compared to aerobic CH 4 oxidation (Rudd et al, 1974).…”

Section: Introductionmentioning

confidence: 99%

Emission and oxidation of methane in a meromictic, eutrophic and temperate lake (Dendre, Belgium)

et al. 2017

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h i g h l i g h t sThe studied lake was meromictic and characterized by high methane, nutrients and sulfate concentrations in the water column. High aerobic and anaerobic methane oxidation rates were observed in the water column, and were dependent on the season. Anaerobic methane oxidation was linked to sulfate reduction, and potentially to nitrate reduction. Despite high methane oxidation rates, methane fluxes to the atmosphere were high. a r t i c l e i n f o a b s t r a c tWe sampled the water column of the Dendre stone pit lake (Belgium) in spring, summer, autumn and winter. Depth profiles of several physico-chemical variables, nutrients, dissolved gases (CO 2 , CH 4 , N 2 O), sulfate, sulfide, iron and manganese concentrations and d 13 C-CH4 were determined. We performed incubation experiments to quantify CH 4 oxidation rates, with a focus on anaerobic CH 4 oxidation (AOM), without and with an inhibitor of sulfate reduction (molybdate). The evolution of nitrate and sulfate concentrations during the incubations was monitored. The water column was anoxic below 20 m throughout the year, and was thermally stratified in summer and autumn. High partial pressure of CO 2 and CH 4 and high concentrations of ammonium and phosphate were observed in anoxic waters. Important nitrous oxide and nitrate concentration maxima were also observed (up to 440 nmol L À1 and 80 mmol L À1 , respectively). Vertical profiles of d 13 C-CH 4 unambiguously showed the occurrence of AOM. Important AOM rates (up to 14 mmol L À1 d À1 ) were observed and often co-occurred with nitrate consumption peaks, suggesting the occurrence of AOM coupled with nitrate reduction. AOM coupled with sulfate reduction also occurred, since AOM rates tended to be lower when molybdate was added. CH 4 oxidation was mostly aerobic (~80% of total oxidation) in spring and winter, and almost exclusively anaerobic in summer and autumn. Despite important CH 4 oxidation rates, the estimated CH 4 fluxes from the water surface to the atmosphere were high (mean of 732 mmol m À2 d À1 in spring, summer and autumn, and up to 12,482 mmol m À2 d À1 in winter).

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“…Anaerobic oxidation of CH 4 (AOM) is known to be coupled to the reduction of sulfate (SO Knittel and Boetius 2009;Ettwig et al 2010). Most studies of AOM have been conducted with marine sediment, and although the specific biochemical mechanisms have not yet been unraveled, the AOM coupled to sulfate reduction (SR) is a well-documented process, occurring in the sulfate-methane transition zone (SMTZ) in marine sediments, where it is performed by a consortium of archaea and sulfate-reducing bacteria (Iversen and Jørgensen 1985;Boetius et al 2000). Here the process is evident from the depth distribution of CH 4 and SO 2{ 4 (Reeburgh 1976;Iversen and Jørgensen 1985) and from stable isotopic composition (d 13 C) of CH 4 (Alperin et al 1988), and it can be directly quantified in incubations with 14 (Iversen and Jørgensen 1985;Treude et al 2005).…”

mentioning

confidence: 99%

“…Most studies of AOM have been conducted with marine sediment, and although the specific biochemical mechanisms have not yet been unraveled, the AOM coupled to sulfate reduction (SR) is a well-documented process, occurring in the sulfate-methane transition zone (SMTZ) in marine sediments, where it is performed by a consortium of archaea and sulfate-reducing bacteria (Iversen and Jørgensen 1985;Boetius et al 2000). Here the process is evident from the depth distribution of CH 4 and SO 2{ 4 (Reeburgh 1976;Iversen and Jørgensen 1985) and from stable isotopic composition (d 13 C) of CH 4 (Alperin et al 1988), and it can be directly quantified in incubations with 14 (Iversen and Jørgensen 1985;Treude et al 2005). AOM coupled to SR efficiently consumes most of the methane produced in marine sediments, but there is little evidence of a role for this process in freshwater sediments, where SR is limited and methanogenesis is favored by sulfate concentrations that are typically 2-3 orders of magnitude lower than in the ocean.…”

mentioning

confidence: 99%

Anaerobic oxidation of methane in an iron‐rich Danish freshwater lake sediment

Nordi

Thamdrup

Schubert

2013

Limnology & Oceanography

145

123

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Freshwater systems are identified as one of the main natural methane sources, but little is known about the importance of anaerobic oxidation of methane (AOM) in these systems. We investigated AOM in a lake sediment characterized by a high reactive iron content, normal sulfate concentrations in the bottom water (, 250 mmol L 21 ), and a relatively deep sulfate penetration of , 14 cm, which facilitated the spatial resolution of the zones of methane production and consumption. Methane concentrations, d 13 C methane profiles, and directly measured and modeled AOM rates all consistently demonstrated methane consumption throughout the anoxic, nitrate-free, Fe(III)-and sulfate-containing zone, oxidizing , 90% of the diffusive methane flux. Thus, the concentration gradient of methane was steepest at the base of the Fe(III) and sulfate zone and decreased strongly toward the sediment surface; while d 13 CH 4 increased from , 280% in the methanogenic zone to 248% in the surface sediment. Direct measurements demonstrated AOM activity throughout the Fe(III) and sulfate zone. AOM rates peaked at sulfate concentrations below 3 mmol L 21 , which suggests a possible coupling of AOM to the reduction of more crystalline Fe(III) oxides. Alternatively, AOM could be coupled to sulfate reduction, which was in turn supported by a cryptic sulfur cycle coupled to Fe(III) reduction. Our results show that AOM can substantially reduce methane emission from freshwater sediments, and the finding of AOM at sulfate concentrations , 3 mmol L 21 suggests that AOM could be of greater importance in freshwater systems, and in ancient low-sulfate oceans, than was previously appreciated.

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Anaerobic methane oxidation rates at the sulfate‐methane transition in marine sediments from Kattegat and Skagerrak (Denmark)1

Cited by 510 publications

References 42 publications

Archaeal lipids in Mediterranean cold seeps: molecular proxies for anaerobic methane oxidation

Archaeal lipids in Mediterranean cold seeps: molecular proxies for anaerobic methane oxidation

Emission and oxidation of methane in a meromictic, eutrophic and temperate lake (Dendre, Belgium)

Anaerobic oxidation of methane in an iron‐rich Danish freshwater lake sediment

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