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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;HCO_3~-和HS~-浓度均升高,前者浓度比后者大2个数量级。Fe~(2+)浓度有所上升,Ca~(2+)浓度则由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。
Sulfate reduction is dominated by sulfate-reducing bacteria (SRB), which is widely distributed in subsea methane seepage deposition zones. When it is coupled with methane oxidation, it plays a controlling role in methane seepage at sea bottom. Studying sulfate reduction is of great significance for exploring the migration and transformation of seabed methane. SRB was inoculated into CH4 under low temperature and high pressure using a reactor as a carrier, and the influence of the geochemical interaction of microorganisms on the chemical composition and environment of the water was discussed. The results showed that the redox potential decreased from -107.5mV to -181.5mV and the concentrations of HCO_3 ~ - and HS ~ - increased. The former concentration was two orders of magnitude higher than the latter. Fe 2+ concentration increased while Ca 2+ concentration decreased from 2.40 mg / L to 0.04 mg / L. Scanning electron microscopy observed more carbonate and sulfide precipitation, energy spectrum analysis found that the main cation of Fe, Ca, Mg and Mn. It can be concluded that sulfate reduction and corresponding geochemical reactions control the variation of ionic species in the system. The results of the experiment are of great significance for understanding the microbial biogeochemistry and marine carbon and sulfur circulation in the seafloor.