Biogeochemical sulfur cycling in the water column of a shallow stratified sea-water lake: Speciation and quadruple sulfur isotope composition
Biogeochemical sulfur cycling in the water column of a shallow stratified sea-water lake: Speciation and quadruple sulfur isotope composition
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DOI：
10.1016/j.marchem.2011.09.001
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发表时间：
2011-12-20
期刊：
影响因子：
3
通讯作者：
Ferdelman, Timothy G.
中科院分区：
文献类型：
--
作者：
Kamyshny, Alexey, Jr.;Zerkle, Aubrey L.;Ferdelman, Timothy G.
分析了克罗地亚罗戈兹尼察湖（Rogoznica Lake）水柱中硫酸盐、硫化物和中间硫的浓度，以及硫酸盐、硫化物和零价硫（ZVS）的四重硫同位素组成。湖的趋化斜层位于8.5-9.5 m深度，支持来自Chromatium属的紫色光养硫化物氧化细菌的密集种群。ZVS （5.42 μ mol L-1）和亚硫酸盐（1.13 μ mol L-1）浓度在趋化cline处最高。在湖底附近检测到硫氰酸盐浓度高达288 nmol L-1。硫氰酸盐剖面表明它是从沉积物中扩散出来的，可能是由氰化物与硫化物氧化中间体的反应产生的。硫酸盐和硫化物之间的多重硫同位素分馏与一个模型一致，即歧化不是趋化斜层以下的主要过程。微生物硫化物氧化是硫循环中再氧化部分的主导过程。尽管在多个硫同位素值中缺乏硫歧化的明确信号，但硫酸盐和硫化物之间的δ S-34分馏在43.8-45.2‰的范围内，与大多数实验室培养研究相比，这是相对较大的。我们的研究结果表明，这种分馏是通过微生物硫酸盐还原单独实现的，这与代谢模型和最近的实验室研究一致。(C) 2011 Elsevier B.V.版权所有
Concentrations of sulfate, sulfide and intermediate sulfur species as well as quadruple sulfur isotope compositions of sulfate, sulfide and zero-valent sulfur (ZVS) were analyzed in the water column of Lake Rogoznica (Croatia), a stratified marine euxinic lake. The chemocline in the lake, which was located at 8.5-9.5 m depth, supports a dense population of purple phototrophic sulfide oxidizing bacteria from the genus Chromatium. The highest ZVS (5.42 mu mol L-1) and sulfite (1.13 mu mol L-1) concentrations were detected at the chemocline. Thiocyanate concentrations up to 288 nmol L-1 were detected near the bottom of the lake. The thiocyanate profile suggests that it diffuses up from the sediment, where it may be produced by the reaction of cyanide with sulfide oxidation intermediates. Multiple sulfur isotope fractionations between sulfate and sulfide were consistent with a model finding that disproportionation is not a dominant process below the chemocline. Microbial sulfide oxidation was found to be the dominant process of the reoxidative part of the sulfur cycle. Despite the absence of a clear signal for sulfur disproportionation in multiple sulfur isotope values, delta S-34 fractionations between sulfate and sulfide were in the range of 43.8-45.2 parts per thousand, is relatively large in comparison to most laboratory culturing studies. Our results suggest that such fractionation is achieved by microbial sulfate reduction alone, which is in agreement with metabolic models and recent laboratory studies. (C) 2011 Elsevier B.V. All rights reserved.