Differential aerobic and anaerobic oxidation of hydrocarbon gases discharged at mud volcanoes in the Nile deep-sea fan Journal Article uri icon

DCO ID 11121/2452-2225-7255-2073-CC

in language

  • eng

year of publication

  • 2009


  • The present study investigates hydrocarbon oxidation processes at Isis and Amon mud volcanoes (MV's), in the eastern Nile deep-sea fan. In the water column, molecular and carbon isotopic signatures of light hydrocarbons indicate that gases rapidly dissolve in seawater and are partially oxidized.|In the upper sediments, anaerobic oxidation of the light hydrocarbons takes place, as clearly shown by their molecular and isotopic composition. These processes lead to the presence of a distinct Sulfate-Hydrocarbon Interface at 120-145 cm and 2050 cm below the seafloor, for Isis and Amon MV's, respectively. In contrast to processes occurring in the water column, a clear preferential oxidation of methane, propane and n-butane over ethane and i-butane is observed in the anoxic sediments. Furthermore, for the first time, fractionation factors have been determined for the anaerobic oxidation of propane and butane, being respectively -4.80 parts per thousand and -0.7 parts per thousand for delta(13)C, and -43.3 parts per thousand for delta(2)H of propane. (C) 2009 Published by Elsevier Ltd.


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