Estimating the impact of seep methane oxidation on ocean pH and dissolved inorganic radiocarbon along the US Mid-Atlantic Bight
Ruppel, Carolyn D.
Kessler, John D.
MetadataShow full item record
Ongoing ocean warming can release methane (CH4) currently stored in ocean sediments as free gas and gas hydrates. Once dissolved in ocean waters, this CH4 can be oxidized to carbon dioxide (CO2). While it has been hypothesized that the CO2 produced from aerobic CH4 oxidation could enhance ocean acidification, a previous study conducted in Hudson Canyon shows that CH4 oxidation has a small short‐term influence on ocean pH and dissolved inorganic radiocarbon. Here we expand upon that investigation to assess the impact of widespread CH4 seepage on CO2 chemistry and possible accumulation of this carbon injection along 234 km of the U.S. Mid‐Atlantic Bight. Consistent with the estimates from Hudson Canyon, we demonstrate that a small fraction of ancient CH4‐derived carbon is being assimilated into the dissolved inorganic radiocarbon (mean fraction of 0.5 ± 0.4%). The areas with the highest fractions of ancient carbon coincide with elevated CH4 concentration and active gas seepage. This suggests that aerobic CH4 oxidation has a greater influence on the dissolved inorganic pool in areas where CH4 concentrations are locally elevated, instead of displaying a cumulative effect downcurrent from widespread groupings of CH4 seeps. A first‐order approximation of the input rate of ancient‐derived dissolved inorganic carbon (DIC) into the waters overlying the northern U.S. Mid‐Atlantic Bight further suggests that oxidation of ancient CH4‐derived carbon is not negligible on the global scale and could contribute to deepwater acidification over longer time scales.
Author Posting. © American Geophysical Union, 2021. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Biogeosciences 126(1), (2021): e2019JG005621, https://doi.org/10.1029/2019JG005621.
Suggested CitationGarcia-Tigreros, F., Leonte, M., Ruppel, C. D., Ruiz-Angulo, A., Joung, D. J., Young, B., & Kessler, J. D. (2021). Estimating the impact of seep methane oxidation on ocean pH and dissolved inorganic radiocarbon along the US Mid-Atlantic Bight. Journal of Geophysical Research: Biogeosciences, 126(1), e2019JG005621.
Showing items related by title, author, creator and subject.
Surface methane concentrations along the mid-Atlantic bight driven by aerobic subsurface production rather than seafloor gas seeps. Leonte, Mihai; Ruppel, Carolyn D.; Ruiz-Angulo, Angel; Kessler, John D. (American Geophysical Union, 2020-04-04)Relatively minor amounts of methane, a potent greenhouse gas, are currently emitted from the oceans to the atmosphere, but such methane emissions have been hypothesized to increase as oceans warm. Here, we investigate the ...
Nutrients and iron in shipboard aerosol and rain samples collected during R/V Hugh R. Sharp cruise HRS1414 in the Mid-Atlantic Bight and northern South-Atlantic Bight from July to August of 2014 (DANCE project) Sedwick, Peter N.; Mulholland, Margaret; Najjar, Raymond (Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: firstname.lastname@example.org, 2019-08-15)Shipboard aerosol and rain samples were collected during R/V Hugh R. Sharp cruise HRS1414 offshore in the Mid-Atlantic Bight and northern South-Atlantic Bight from July to August of 2014. Samples were analyzed for nutrients ...
Zhang, Weifeng G.; Gawarkiewicz, Glen G. (John Wiley & Sons, 2015-09-30)Onshore intrusions of offshore waters onto the Mid-Atlantic Bight shelf can greatly affect shelf circulation, biogeochemistry, and fisheries. Previous studies have concentrated on onshore intrusions of slope water. Here ...