甲烷渗漏环境中硫酸盐还原对水化学组分的影响

硫酸盐还原作用是由硫酸盐还原菌(SRB)主导的，它广泛分布于海底甲烷渗漏沉积区。当它与甲烷氧化耦联时，对海底甲烷渗漏起着控制作用。研究硫酸盐还原作用对于探讨海底甲烷的迁移和转化具有重要意义。以反应釜为载体，将SRB接种于低温高压的甲烷环境中，探讨系统内微生物地球化学作用对水化学组分和环境的影响规律。结果显示：系统内氧化还原电位由-107.5mV降低至-181.5mV；HCO₃^-和HS^-浓度均升高，前者浓度比后者大2个数量级。Fe²⁺浓度有所上升，Ca²⁺度则由2.40mg/L降低至0.04mg/L。扫描电镜下观测到有较多的碳酸盐和硫化物沉淀，能谱分析发现其主要阳离子为Fe、Ca、Mg和Mn。可以确定，硫酸盐还原作用及相应的地球化学反应控制着系统内离子组分的变化。实验结果对认识海底发生的微生物地球化学作用和海洋碳硫循环有重要意义。

The Sulfate Reduction Effect on Water Chemical Compositionsin Methane Seeping Environment

Sulfate reduction is induced by the sulfate-reducing bacteria (SRB),and it is widely distributed in methane seeps in marine environment.Sulfate reduction plays an important role in controlling the methane seeps whilst it couples to anaerobic oxidation of methane.Therefore,it is of great significance to research the sulfate reduction to discuss methane transfer and transformation in submarine sediment.To study the impact of biogeochemical reactions on the hydrochemical compositions and environment,high-pressure reactor kettle acts as an SRB carrier,and it has inoculated SRB with the methane environment under low-temperature and high-pressure.The results revealed that the Oxidation Reduction Potential value has decreased from -107.5mV to -181.5mV in the reactor.Both the concentrations ofHCO₃^- and HS^- have decreased with time growth,and the former concentration was 2 orders of magnitude larger than the latter.The concentration ofFe²⁺ increased to some extent,but Ca²⁺ reduced from 2.40mg/L to 0.04 mg/L.There were many carbonate and sulfide minerals detected by the SEM,and the components of precipitations were Fe,Ca,Mg and Mn analyzed by EDS.It can be concluded that sulfate reduction and the corresponding geochemical reaction control the changes of ion components in this system.The experiment results have certain significance for understanding the biogeochemical reactions and carbon-sulfur cycle in submarine sediment.