Stable isotope biogeochemistry of the sulfur cycle in modern marine sediments: I. seasonal dynamics in a temperate intertidal sandy surface sediment
Stable isotope biogeochemistry of the sulfur cycle in modern marine sediments: I. seasonal dynamics in a temperate intertidal sandy surface sediment
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现代海洋沉积物中硫循环的稳定同位素生物地球化学：I.温带潮间带沙质表层沉积物的季节动态
DOI：
10.1080/10256010410001678071
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发表时间：
2004
影响因子：
1.3
通讯作者：
K. Bosselmann
中科院分区：
文献类型：
--
作者：
M. Böttcher;Britta Hespenheide;H. Brumsack;K. Bosselmann
对有机质贫乏的温带潮间带沙质表层沉积物（北海德国瓦登海）的表层沉积物进行了生物地球化学和稳定同位素地球化学研究，以研究硫酸盐还原菌的活性以及沉积物硫、铁和锰物种垂直分配的动态与总有机碳（TOC）和泥含量的关系。测量了总还原无机硫物种（TRIS）和溶解硫酸盐的含量和稳定同位素组成（34S/32S）。最大氧气渗透深度是从沉积物因 FeS 积累而变黑开始时估计的，范围为地表以下 5 至 10 毫米 (mmbsf)。在 5 至 20 mmbsf 之间发现了一个相对中等的相对有机物富集区域，导致硫酸盐还原细菌的活性增强，硫酸盐还原率 (SRR) 高达 350 nmol cm−3 d−1。低于该区域，微生物 SRR 显着下降。深度积分 SRR 似乎不仅取决于温度，还取决于活性有机物的可用性。相对于共存的溶解硫酸盐，TRIS 的硫同位素组成在 34S 中减少了 33-40 ‰（与维也纳峡谷 Diablo Troilite (V-CDT) 相比，恒定在 +21 ‰ 左右）。由于硫酸盐还原不受溶解硫酸盐（开放系统）的限制，TRIS同位素组成的深度变化反映了由于叠加的微生物和非生物反应而导致的总体同位素效应的变化。大多数固相铁和锰与（非反应性）重矿物结合。然而，由于沉积物-水界面处溶解的 Fe(II) 和 Mn(II) 物质的再氧化，在最上面的沉积物部分发现了一层活性 Fe(III) 和 Mn(IV) 氧化物（氢氧化物）。表面以下的金属循环至少部分与强烈的硫循环相关。
A biogeochemical and stable isotope geochemical study was carried out in surface sediments of an organic-matter poor temperate intertidal sandy surface sediment (German Wadden Sea of the North Sea) to investigate the activity of sulfate-reducing bacteria and the dynamics of the vertical partitioning of sedimentary sulfur, iron, and manganese species in relation to the availability of total organic carbon (TOC) and mud contents. The contents and stable isotopic compositions (34S/32S) of total reduced inorganic sulfur species (TRIS) and dissolved sulfate were measured. Maximum oxygen penetration depths were estimated from the onset of a blackening of the sediments due to FeS accumulation and ranged from 5 to 10 mm below surface (mmbsf). A zone of relatively moderate relative organic-matter enrichment was found between 5 and 20 mmbsf leading to enhanced activities of sulfate-reducing bacteria with sulfate-reduction rates (SRR) up to 350 nmol cm−3 d−1. Below this zone, microbial SRR dropped significantly. Depth integrated SRR seem to depend not only on temperature but also on the availability of reactive organic matter. The sulfur-isotopic composition of TRIS was depleted in 34S by 33–40 ‰ with respect to coexisting dissolved sulfate (constant at about +21 ‰ vs. Vienna-Canyon Diablo Troilite (V-CDT)). Since sulfate reduction is not limited by dissolved sulfate (open system), depth variations of the isotopic composition of TRIS reflect changes in overall isotope effect due to superimposed microbial and abiotic reactions. Most of the solid-phase iron and manganese was bonded to (non-reactive) heavy minerals. However, a layer of reactive Fe(III) and Mn(IV) oxi(hydroxi)des was found in the uppermost sediment section due to re-oxidation of dissolved Fe(II) and Mn(II) species at the sediment–water interface. Metal cycling below the surface is at least partially coupled to intense sulfur cycling.