Wei Chenhui, Yin Shujun, Kappler Andreas, Tao Shu, Zhu Dongqiang
School of Urban and Environmental Sciences, Key Laboratory of the Ministry of Education for Earth Surface Processes, Peking University, Beijing 100871, China.
Geomicrobiology, Department of Geoscience, University of Tuebingen, Tuebingen 72076, Germany.
Fundam Res. 2023 Sep 14;5(4):1607-1613. doi: 10.1016/j.fmre.2023.08.003. eCollection 2025 Jul.
Although pyrite is the main sedimentary form of sulfur, an ample mechanistic comprehension of its formation in low-sulfate environments is lacking. Applying high depth-resolution multigeochemical and stable sulfur isotope composition (δS) analysis of a sediment core recovered from a large shallow freshwater lake (Baiyangdian) in north China, we show that the pyrite forms dominantly in the top 4 cm layer and the participating sulfide stems primarily from mineralization of reduced organic sulfur in biomass. This mechanism was further verified by the formation of pyrite in anoxic incubation of biomass ( L. or ) with hematite in the absence of external sulfate. This finding reveals an alternative pathway other than microbial sulfate reduction (MSR) for producing sulfide to form pyrite in low-sulfate sediments.
尽管黄铁矿是硫的主要沉积形式，但目前仍缺乏对其在低硫酸盐环境中形成机制的充分理解。通过对从中国北方一个大型浅水淡水湖（白洋淀）采集的沉积物岩芯进行高深度分辨率的多地球化学和稳定硫同位素组成（δS）分析，我们发现黄铁矿主要形成于顶部4厘米的层中，参与其中的硫化物主要来源于生物量中还原态有机硫的矿化作用。在没有外部硫酸盐的情况下，生物量（L. or）与赤铁矿进行缺氧培养时黄铁矿的形成进一步证实了这一机制。这一发现揭示了在低硫酸盐沉积物中，除了微生物硫酸盐还原（MSR）之外，另一种产生硫化物以形成黄铁矿的途径。
