Beeman R E, Suflita J M
Department of Botany and Microbiology, University of Oklahoma, Norman 73019.
J Ind Microbiol. 1990 Jan;5(1):45-57. doi: 10.1007/BF01569605.
The environmental factors influencing methanogenesis in a shallow anoxic aquifer were probed in a combined field and laboratory study. Field data collected over a year revealed that 'in situ' rates of methane production were depressed in winter and elevated in summer. Over the same period, ground water pH values ranged from 6.0 to 7.8 while temperatures varied from 7-22 degrees C. 'In situ' methanogenesis was severely inhibited at temperatures less than 13 degrees C or by pH values less than 7. The influence of these factors on microbial methane formation from both endogenous and exogenous substrates were tested in aquifer slurries adjusted to pH 5-9 and incubated at temperatures ranging from 5-45 degrees C. Temperature optima for methane production from endogenous substrates varied as a function of pH, but the pH optimum was 8 at all temperatures. Optimal conditions for acetoclastic methanogenesis were found at pH 8 and 35 degrees C. An analysis of variance revealed that pH, temperature, and a pH-temperature interaction are all significant variables influencing aquifer methanogenesis. In addition transient sulfate accumulations were also found to limit methane production in some areas. A comparison of field and laboratory methane production patterns suggest that pH, temperature, and sulfate accumulations are important, but not the only environmental variables influencing the mineralization of organic matter in shallow aquifers.
通过一项结合了现场和实验室研究的项目，对影响浅层缺氧含水层中甲烷生成的环境因素进行了探究。一年多来收集的现场数据显示，甲烷的“原位”生成速率在冬季较低，而在夏季较高。在同一时期，地下水的pH值在6.0至7.8之间，温度则在7至22摄氏度之间变化。当温度低于13摄氏度或pH值低于7时，“原位”甲烷生成会受到严重抑制。在将含水层泥浆的pH值调节至5至9，并在5至45摄氏度的温度下孵育的条件下，测试了这些因素对微生物从内源性和外源性底物生成甲烷的影响。内源性底物生成甲烷的最适温度随pH值变化，但在所有温度下，最适pH值均为8。在pH值为8和35摄氏度的条件下，发现了乙酸裂解产甲烷的最佳条件。方差分析显示，pH值、温度以及pH值与温度的相互作用都是影响含水层甲烷生成的重要变量。此外，还发现一些地区的瞬时硫酸盐积累也会限制甲烷的生成。对现场和实验室甲烷生成模式的比较表明，pH值、温度和硫酸盐积累很重要，但并非影响浅层含水层中有机物矿化的唯一环境变量。
