State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Room 504, Mingjing Building, Shanghai 200092, P.R. China.
PowerChina Huadong Engineering Corporation Limited, Hangzhou 311122, China.
Environ Sci Technol. 2020 May 5;54(9):5498-5508. doi: 10.1021/acs.est.9b05740. Epub 2020 Apr 22.
The sulfur cycle is an important part of constructed wetland biogeochemistry because it is intimately intertwined with the carbon, nitrogen, and iron cycles. However, to date, no quantitative investigation has been conducted on the sulfur cycle in constructed wetlands because of the complexity of wetland systems and the deficiencies in experimental methodology. In this study, S-stable isotope analysis was extended in terms of the calculation for the enrichment factor and the kinetic analysis for bacterial sulfate reduction. With this extended method, we attempted for the first time to assess the true rate of bacterial sulfate reduction when sulfide oxidation co-occurs. The joint application of the extended S-stable isotope and mass balance analyses made it possible to quantitatively investigate the primary sulfur transformation in a wetland microcosm. Accordingly, a sulfur cycle model for constructed wetlands was quantified and validated. Approximately 75% of the input sulfur was discharged. The remainder was mainly removed through deposition as acid volatile sulfide, pyrite, and elemental sulfur. Plant uptake was negligible. These findings improve our understanding of the physical, chemical, and biological transformations of sulfur among plants, sediments, and microorganisms, and their interactions with carbon, nitrogen, and iron cycles, in constructed wetlands and similar systems.
硫循环是人工湿地生物地球化学的重要组成部分，因为它与碳、氮和铁循环密切交织在一起。然而，由于湿地系统的复杂性和实验方法的不足，迄今为止，还没有对人工湿地中的硫循环进行定量研究。在这项研究中，我们扩展了 S 稳定同位素分析，包括计算富集因子和细菌硫酸盐还原的动力学分析。通过这种扩展的方法，我们首次尝试评估硫化物氧化同时发生时细菌硫酸盐还原的真实速率。扩展的 S 稳定同位素和质量平衡分析的联合应用使得在湿地微宇宙中定量研究主要的硫转化成为可能。因此，量化并验证了人工湿地的硫循环模型。大约 75%的输入硫被排放。其余的主要通过作为酸可挥发硫、黄铁矿和元素硫的沉积而被去除。植物吸收可以忽略不计。这些发现提高了我们对植物、沉积物和微生物之间硫的物理、化学和生物转化及其与碳、氮和铁循环相互作用的理解，这些过程在人工湿地和类似系统中发生。
