title: Effects of sulfate-reducing bacteria on methylmercury at the sediment-water interface.
abstract: Sediment cores (containing sediment and overlying water) from Baihua Reservoir (SW China) were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria (SRB) on mercury (Hg) methylation at sediment-water interfaces. Concentrations of dissolved methyl mercury (DMeHg) in the overlying water of the control cores with bioactivity maintained (BAC) and cores with only sulfate-reducing bacteria inhibited (SRBI) and bacteria fully inhibited (BACI) were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMeHg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations (r=-0.5311 and r=-0.4977 for BAC and SRBI, respectively). The water DMeHg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment-water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster (hgcAB), besides SRB, causing Hg methylation in the sediment-water system.
authors: Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang 550003, China. Electronic address: zenglingxia2010@163.com.
authors: Lingxia
authors: L
authors: Zeng
authors: Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang 550003, China.
authors: Guangjun
authors: G
authors: Luo
authors: Key Laboratory of Karst Environment and Geohazard Prevention, Guizhou University, Guiyang 550003, China. Electronic address: hetianrong@139.com.
authors: Tianrong
authors: T
authors: He
authors: Power China Guiyang Engineering Corporation Limited, Guiyang 550081, China.
authors: Yanna
authors: Y
authors: Guo
authors: The School of Resources and Environment Engineering, Guizhou University, Guiyang 550003, China.
authors: Xiaoli
authors: X
authors: Qian
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D008767:Methylmercury Compounds / Q000032:analysis / Q000378:metabolism*; D013431:Sulfates / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D008767:Methylmercury Compounds; D013431:Sulfates; D014874:Water Pollutants, Chemical
keywords: Methyl mercury; Microbial activity; Redox condition; Sediment–water interface; Sulfate-reducing bacteria