Methane, manganese, and helium in hydrothermal plumes following volcanic eruptions on the East Pacific Rise near 9°50′N
Love, Brooke A.
Resing, Joseph A.
Cowen, James P.
Lupton, John E.
Fornari, Daniel J.
Shank, Timothy M.
MetadataShow full item record
As part of a rapid response cruise in May 2006, we surveyed water column hydrothermal plumes and bottom conditions on the East Pacific Rise between 9°46.0′N and 9°57.6′N, where recent seafloor volcanic activity was suspected. Real-time measurements included temperature, light transmission, and salinity. Samples of the plume waters were analyzed for methane, manganese, helium concentrations, and the δ 13C of methane. These data allow us to examine the effects of the 2005–2006 volcanic eruption(s) on plume chemistry. Methane and manganese are sensitive tracers of hydrothermal plumes, and both were present in high concentrations. Methane reached 347 nM in upper plume samples (250 m above seafloor) and exceeded 1085 nM in a near-bottom sample. Mn reached 54 nM in the upper plume and 98 nM in near-bottom samples. The concentrations of methane and Mn were higher than measurements made after a volcanic eruption in the same area in 1991, but the ratio of CH4/Mn, at 6.7, is slightly lower, though still well above the ratios measured in chronic plumes. High concentrations of methane in near-bottom samples were associated with areas of microbial mats and diffuse venting documented in seafloor imagery. The isotopic composition of the methane carbon shows evidence of active microbial oxidation; however, neither the fractionation factor nor the source of the eruption-associated methane can be determined with any certainty. Considerable scatter in the isotopic data is due to diverse sources for the methane as well as fractionation as methane is consumed. One sample at +21‰ versus Peedee belemnite standard is among the most enriched methane carbon values reported in a hydrothermal plume to date.
Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 9 (2008): Q06T01, doi:10.1029/2008GC002104.
Showing items related by title, author, creator and subject.
Dissolved methane distributions and air-sea flux in the plume of a massive seep field, Coal Oil Point, California Mau, Susan; Valentine, David L.; Clark, Jordan F.; Reed, Justin; Camilli, Richard; Washburn, Libe (American Geophysical Union, 2007-11-24)Large quantities of natural gas are emitted from the seafloor into the stratified coastal ocean near Coal Oil Point, Santa Barbara Channel, California. Methane was quantified in the down current surface water at 79 stations ...
Microbial diversity of hydrothermal sediments in the Guaymas Basin : evidence for anaerobic methanotrophic communities Teske, Andreas; Hinrichs, Kai-Uwe; Edgcomb, Virginia P.; de Vera Gomez, Alvin; Kysela, David; Sylva, Sean P.; Sogin, Mitchell L.; Jannasch, Holger W. (American Society for Microbiology, 2002-04)Microbial communities in hydrothermally active sediments of the Guaymas Basin (Gulf of California, Mexico) were studied by using 16S rRNA sequencing and carbon isotopic analysis of archaeal and bacterial lipids. The Guaymas ...
Analysis and modeling of hydrothermal plume data acquired from the 85°E segment of the Gakkel Ridge Stranne, Christian; Sohn, Robert A.; Liljebladh, Bengt; Nakamura, Ko-ichi (American Geophysical Union, 2010-06-30)We use data from a CTD plume-mapping campaign conducted during the Arctic Gakkel Vents (AGAVE) expedition in 2007 to constrain the nature of hydrothermal processes on the Gakkel Ridge at 85°E. Thermal and redox potential ...