Low-temperature formation of hydrocarbon gases in San Francisco Bay sediment (California, U.S.A.)

Chemical Geology
By: , and 

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Abstract

To understand the processes responsible for the presence of low-molecular-weight hydrocarbons (C1-C4) in anoxic environments, we studied sediments collected from an anaerobic estuarine mudflat. In these sediments methane (C1) was several orders of magnitude more abundant than all other C2-C4 hydrocarbons; the C1 (C2 + C3) ratio was ??? 13,000. Mean ethane/ethene and propane/propene ratios were 0.4 and 0.7, respectively. Production of C1-C4 hydrocarbons was monitored during prolonged incubation (7 months) of sediments at 27?? and 4??C. Samples stored at 27??C generated significant quantities of C1-C4 hydrocarbon gases. Incubation at 4??C inhibited production of these gases. Several bactericides were tested with respect to their ability to inhibit formation of gaseous hydrocarbons. Sodium azide, chloroform, and 2-bromoethanesulfonic acid effectively inhibited methane formation, but not ethene formation in dilute continuously-shaken sediment slurries. Zephiran chloride only caused partial inhibition of methanogenesis (46%) and ethene generation (34%) in these slurries. In experiments with more concentrated unshaken sediment slurries, however, zephiran chloride and sodium azide did not block formation of methane, ethane, or propane. Only storage at -10??C prevented production of these gases. These results indicate that C1-C4 hydrocarbons can be formed by low-temperature reactions, possibly mediated by microorganisms. ?? 1982.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Low-temperature formation of hydrocarbon gases in San Francisco Bay sediment (California, U.S.A.)
Series title Chemical Geology
DOI 10.1016/0009-2541(82)90084-5
Volume 37
Issue 3-4
Year Published 1982
Language English
Publisher Elsevier
Contributing office(s) San Francisco Bay-Delta, Pacific Regional Director's Office
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Chemical Geology
First page 289
Last page 298
Online Only (Y/N) N
Additional Online Files (Y/N) N