Methane production in littoral sediment of Lake Constance
Methane production in littoral sediment of Lake Constance
复制标题
博登湖沿岸沉积物中的甲烷产量
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
R. Conrad
中科院分区：
文献类型：
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作者：
B. Thebrath;F. Rothfuss;M. Whiticar;R. Conrad
在沿岸的沉积物中，2-5厘米深度的甲烷产生率最高。甲烷的生产率在这一年中从12月的约5 mmol m−2d−1增加到9月的最高约95 mmol m−2d−1。CH 4的生成速率显示最佳温度为30°C，表观活化能为76 kJ mol−1。沉积物温度的变化在很大程度上反映了CH 4产生的季节性。大部分产生的CH 4通过沸腾损失。气泡含有约60-70%的CH 4，平均δ 13 C为−56.2%，δD为− 354%，以及2%的CO2，平均δ 13 C为−14.1%，表明CH 4是由甲基碳产生的，即主要使用乙酸盐作为产甲烷底物。这一结果通过用氯仿抑制甲烷生成得到证实，这导致乙酸盐的积累速率相当于CH 4产生速率的81%。产甲烷细菌的最大可能数量为104个细菌g-1d.w。利用乙酸盐、甲醇或甲酸盐的产甲烷菌的沉降率为105，利用H2的产甲烷菌的沉降率为105。乙酸盐的周转时间约为2.3-4.8小时，其中原位乙酸盐浓度约为25-50 μM，导致乙酸盐周转率与CH 4产生率相当。呼吸指数（RI）表明，[2− 14 C]乙酸盐主要用于甲烷生成，而不是呼吸过程，尽管沉积物中CH 4产生区与硫酸盐还原区重叠。
Maximum rates of CH4 production in the littoral sediment were observed in 2–5 cm depth. The CH4 production rates increased during the year from about 5 mmol m−2d−1 in December to a maximum of about 95 mmol m−2d−1 in September. CH4 production rates showed a temperature optimum at 30°C and an apparent activation energy of 76 kJ mol−1. A large part of the seasonality of CH4 production could be ascribed to the change of the sediment temperature. Most of the produced CH4 was lost by ebullition. Gas bubbles contained about 60–70% CH4 with an average δ13C of −56.2% and δD of −354%, and 2% CO2 with an average δ13C of −14.1% indicating that CH4 was produced from methyl carbon, i.e. mainly using acetate as methanogenic substrate. This result was confirmed by inhibition of methanogenesis with chloroform which resulted in an accumulation rate of acetate equivalent to 81% of the rate of CH4 production. Most probable numbers of methanogenic bacteria were in the order of 104 bacteria g−1d.w. sediment for acetate-, methanol- or formate-utilizing, and of 105 for H2-utilizing methanogens. The turnover times of acetate were in the order of 2.3–4.8 h which, with in situ acetate concentrations of about 25–50 μM, resulted in rates of acetate turnover which were comparable to the rates of CH4 production. The respiratory index (RI) showed that [2−14C]acetate was mainly used by methanogenesis rather than by respiratory processes, although the zone of CH4 production in the sediment overlapped with the zone of sulfate reduction.