甲烷厌氧氧化作用:来自珠江口淇澳岛海岸带沉积物间隙水的地球化学证据被引量：20

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摘要对珠江口淇澳岛海岸带沉积物间隙水中甲烷、硫酸盐、CH4-δ13C和ΣCO2-δ13C的地球化学参数垂直剖面特征的研究结果显示:甲烷浓度梯度在硫酸盐还原带底部急剧增大,而间隙水硫酸盐浓度随深度呈线性降低;在硫酸盐-甲烷转换带(SMT)中,甲烷碳同位素逐渐变重,并引起间隙水ΣCO2-δ13C值变为极负.间隙水地球化学参数的变化特征提供了该区域沉积物中存在AOM作用的证据.根据数学模型计算出的三个站位甲烷厌氧氧化速率和硫酸盐还原速率,可知AOM消耗的硫酸盐占总硫酸盐损耗的比例分别为9.0%,84%和45.5%,对应的AOM产生的ΣCO2占总CO2的比例分别为4.7%,72.4%和29.45%.有机质的输入量的大小影响沉积物底部甲烷浓度、扩散通量及SMT分布.较高的有机质输入量一方面有利于加速间隙水硫酸盐通过有机质矿化分解作用损耗,另一方面引起进入SMT的甲烷扩散通量增大,使得AOM过程硫酸盐的消耗量相应增大,结果造成SMT向沉积物表层上移.

作者吴自军周怀阳彭晓彤陈光谦

机构地区中国科学院广州地球化学研究所

出处《科学通报》 EI CAS CSCD 北大核心 2006年第17期2052-2059,共8页 Chinese Science Bulletin

基金国家重点基础研究发展计划项目(批准号:G2000078500) 中国科学院知识创新前沿项目(批准号:GIGCx-03-07)资助.

关键词甲烷厌氧氧化硫酸盐还原沉积物珠江口

分类号 P736.21 [天文地球—海洋地质]

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