Evidence for the existence of psychrophilic methanogenic communities in anoxic sediments of deep lakes

In order to obtain evidence for the existence of psychrophilic methanogenic communities in sediments of deep lakes that are low-temperature environments (4 to 5degreesC), slurries were first incubated at temperatures between 4 and 60degreesC for several weeks, at which time they were amended, or not, with an additional substrate, such as cellulose, butyrate, propionate, acetate, or hydrogen, and further incubated at 6degreesC. Initial methane production rates were highest in slurries preincubated at temperatures between 4 and 15degreesC, with maximal rates in slurries kept at 6degreesC. Hydrogen-amended cultures were the only exceptions, with the highest methane production rates at 6degreesC after preincubation at 30degreesC.