Effects of temperature and pressure on sulfate reduction and anaerobic oxidation of methane in hydrothermal sediments of Guaymas Basin

Rates of sulfate reduction (SR) and anaerobic oxidation of methane (AOM) in hydrothermal deep-sea sediments from Guaymas Basin were measured at temperatures of 5 to 200 degrees C and pressures of 1 x 10(5), 2.2 x 10(7), and 4.5 x 10(7) Pa. A maximum SR of several micromoles per cubic centimeter per day was found at between 60 and 95 degrees C and 2.2 x 10(7) and 4.5 x 10(7) Pa. Maximal AOM was observed at 35 to 90 degrees C but generally accounted for less than 5% of SR.