Stable isotopic evidence in support of active microbial methane cycling in low-temperature diffuse flow vents at 9°50’N East Pacific Rise
MetadataShow full item record
KeywordMethane; Carbon dioxide; Diffuse fluid; Hydrothermal vents; Methanogenesis; Methane oxidation
A unique dataset from paired low- and high-temperature vents at 9°50’N East Pacific Rise provides insight into the microbiological activity in low-temperature diffuse fluids. The stable carbon isotopic composition of CH4 and CO2 in 9°50’N hydrothermal fluids indicates microbial methane production, perhaps coupled with microbial methane consumption. Diffuse fluids are depleted in 13C by ~10‰ in values of δ13C of CH4, and by ~0.55‰ in values of δ13C of CO2, relative to the values of the high-temperature source fluid (δ13C of CH4 = -20.1 ± 1.2‰, δ13C of CO2 = -4.08 ± 0.15‰). Mixing of seawater or thermogenic sources cannot account for the depletions in 13C of both CH4 and CO2 at diffuse vents relative to adjacent high-temperature vents. The substrate utilization and 13C fractionation associated with the microbiological processes of methanogenesis and methane oxidation can explain observed steady-state CH4 and CO2 concentrations and carbon isotopic compositions. A mass-isotope numerical box-model of these paired vent systems is consistent with the hypothesis that microbial methane cycling is active at diffuse vents at 9°50’N. The detectable 13C modification of fluid geochemistry by microbial metabolisms may provide a useful tool for detecting active methanogenesis.
Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 72 (2008): 2005-2023, doi:10.1016/j.gca.2008.01.025.
Suggested CitationPreprint: Proskurowski, Giora, Lilley, Marvin D., Olson, Eric J., "Stable isotopic evidence in support of active microbial methane cycling in low-temperature diffuse flow vents at 9°50’N East Pacific Rise", 2008-01, https://doi.org/10.1016/j.gca.2008.01.025, https://hdl.handle.net/1912/2236
Showing items related by title, author, creator and subject.
Simultaneous determination of thermal conductivity, thermal diffusivity and specific heat in sI methane hydrate Waite, William F.; Stern, Laura A.; Kirby, S. H.; Winters, William J.; Mason, D. H. (Blackwell Publishing, 2007-03-11)Thermal conductivity, thermal diffusivity and specific heat of sI methane hydrate were measured as functions of temperature and pressure using a needle probe technique. The temperature dependence was measured between −20°C ...
Modeling sulfate reduction in methane hydrate-bearing continental margin sediments : does a sulfate-methane transition require anaerobic oxidation of methane? Malinverno, Alberto; Pohlman, John W. (American Geophysical Union, 2011-07-12)The sulfate-methane transition (SMT), a biogeochemical zone where sulfate and methane are metabolized, is commonly observed at shallow depths (1–30 mbsf) in methane-bearing marine sediments. Two processes consume sulfate ...
Correction to “Elastic wave speeds and moduli in polycrystalline ice Ih, sI methane hydrate, and sII methane-ethane hydrate” Helgerud, M. B.; Waite, William F.; Kirby, S. H.; Nur, A. (American Geophysical Union, 2009-04-10)