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Anaerobic oxidation of methane above gas hydrates at Hydrate Ridge, NE Pacific Ocean
- Source :
- Treude, T, Boetius, A, Knittel, K, Wallmann, K & Jørgensen, BB 2003, ' Anaerobic oxidation of methane above gas hydrates at Hydrate Ridge, NE Pacific Ocean ', Marine Ecology-Progress Series, vol. 264, pp. 1-14 ., Scopus-Elsevier, Aarhus University, Marine Ecology-Progress Series
- Publication Year :
- 2003
-
Abstract
- At Hydrate Ridge (HR), Cascadia convergent margin, surface sediments contain massive gas hydrates formed from methane that ascends together with fluids along faults from deeper reservoirs. Anaerobic oxidation of methane (AOM), mediated by a microbial consortium of archaea and sulfate-reducing bacteria, generates high concentrations of hydrogen sulfide in the surface sediments. The production of sulfide supports chemosynthetic communities that gain energy from sulfide oxidation. Depending on fluid flow, the surface communities are dominated either by the filamentous sulfur bacteria Beggiatoa (high advective flow), the clam Calyptogena (low advective flow), or the bivalve Acharax (diffusive flow). We analyzed surface sediments (0 to 10 cm) populated by chemosynthetic communities for AOM, sulfate reduction (SR) and the distribution of the microbial consortium mediating AOM. Highest AOM rates were found at the Beggiatoa field with an average rate of 99 mmol m(-2) d(-1) integrated over 0 to 10 cm. These rates are among the highest AOM rates ever observed in methane-bearing marine sediments. At the Calyptogena field, AOM rates were lower (56 mmol m(-2) d(-1)). At the Acharax field, methane oxidation was extremely low (2.1 mmol m(-2) d(-1)) and was probably due to aerobic oxidation of methane. SR was fueled largely by methane at flow-impacted sites, but exceeded AOM in some cases, most likely due to sediment heterogeneity. At the Acharax field, SR was decoupled from methane oxidation and showed low activity. Aggregates of the AOM consortium were abundant at the fluid-impacted sites (between 5.1 x 10(12) and 7.9 x 10(12) aggregates m(-2)) but showed low numbers at the Acharax field (0.4 x 10(12) aggregates m(-2)). A transportreaction model was applied to estimate AOM at Beggiatoa fields. The model agreed with the measured depth-integrated AOM rates and the vertical distribution. AOM represents an important methane sink in the surface sediments of HR, consuming between 50 and 100 % of the methane transported by advection.
- Subjects :
- chemistry.chemical_classification
Chemosynthesis
010504 meteorology & atmospheric sciences
Ecology
biology
Sulfide
Hydrate Ridge
Clathrate hydrate
Mineralogy
Aquatic Science
010502 geochemistry & geophysics
Beggiatoa
biology.organism_classification
01 natural sciences
6. Clean water
Cold seep
Methane
chemistry.chemical_compound
chemistry
13. Climate action
Anaerobic oxidation of methane
otorhinolaryngologic diseases
14. Life underwater
Ecology, Evolution, Behavior and Systematics
0105 earth and related environmental sciences
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Treude, T, Boetius, A, Knittel, K, Wallmann, K & Jørgensen, BB 2003, ' Anaerobic oxidation of methane above gas hydrates at Hydrate Ridge, NE Pacific Ocean ', Marine Ecology-Progress Series, vol. 264, pp. 1-14 ., Scopus-Elsevier, Aarhus University, Marine Ecology-Progress Series
- Accession number :
- edsair.doi.dedup.....7cd92bc04192f0a9ade804d51a913301