Modeling of biogeochemical processes in a barrier island freshwater lens (Spiekeroog, Germany)
Modeling of biogeochemical processes in a barrier island freshwater lens (Spiekeroog, Germany)
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障壁岛淡水透镜体中生物地球化学过程的建模（Spiekeroog，德国）
DOI：
10.1016/j.jhydrol.2019.05.094
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发表时间：
2019
影响因子：
6.4
通讯作者：
Massmann
中科院分区：
文献类型：
--
作者：
Seibert;Greskowiak;Prommer;Böttcher;Massmann
淡水透镜体为屏障岛屿提供了宝贵的水资源。然而，控制这些淡水透镜体的地下水质量的生物地球化学过程以及它们如何受到当前地下水动态的影响在很大程度上是未知的。在这项研究中，我们调查了屏障岛淡水透镜的地球化学，重点是了解和量化的有机质矿化，硫循环和化学通量的陆地-海洋界面。我们分析了一套全面的水文地球化学场数据从Spiekeroog岛（德国），包括溶解硫物种的稳定硫同位素的签名，与反应传输建模方法。氚-氦地下水年龄被用来约束作为停留时间的函数的水文地球化学。我们的研究结果表明，淡水透镜体可以作为人为污染的档案，保存与历史大气沉积相关的高硫负荷。我们观察到两种不同的（水）地球化学模式，我们归因于一个不均匀分布的活性有机质。这些模式很好地复制了两个独立的反应运输模型，认为在有机物的反应性的变化。模拟和现场结果表明，净硫循环是由微生物硫酸盐还原和随后的硫化铁沉淀。在没有溶解氧化剂的情况下，我们将观察到的溶解硫酸盐和硫化物之间高达67‰的高稳定硫同位素分馏归因于低（<20 pmol mL−1d−1）微生物硫酸盐还原速率。我们发现，老年人的地下水逐渐成为丰富的铵和磷酸盐，由于有机物的矿化，我们推测，透镜衍生的营养通量可能是重要的底栖区在当地的地下水排放点，至少在春季和夏季的季节。
Freshwater lenses present valuable water resources on barrier islands. Yet, the biogeochemical processes that control the groundwater quality of these freshwater lenses and how they are affected by the prevailing groundwater dynamics is largely unexplored. In this study we investigated the biogeochemistry of a barrier island freshwater lens with a focus on understanding and quantifying organic matter mineralization, sulfur cycling, and chemical fluxes to the land-ocean interface. We analyzed a comprehensive set of hydrogeochemical field data from Spiekeroog Island (Germany), including stable sulfur isotope signatures of dissolved sulfur species, with a reactive transport modeling approach. Tritium-Helium groundwater ages were used to constrain the hydrogeochemistry as a function of residence time. Our results revealed that freshwater lenses can act as archives for anthropogenic pollution, conserving the high sulfur loads associated with historic atmospheric deposition. We observed two distinct (hydro)biogeochemical patterns, which we attribute to a heterogeneous distribution of reactive organic matter. Those patterns were well replicated by two separate reactive transport models that considered the variations in organic matter reactivity. Simulation and field results demonstrated that net sulfur cycling is dominated by microbial sulfate reduction and subsequent iron sulfide precipitation. In the absence of dissolved oxidants, we attribute the observed high stable sulfur isotope fractionation between dissolved sulfate and sulfide of up to 67‰ to low (<20 pmol mL−1d−1) microbial sulfate reduction rates. We show that older groundwater becomes progressively enriched in ammonium and phosphate due to the mineralization of organic matter, and we speculate that lens-derived nutrient fluxes may be important for the benthic zone at local groundwater discharge sites, at least seasonally in spring and summer.
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影响因子：
5.4
作者：
G. Houben;P. Koeniger;J. Sültenfuss
通讯作者：
G. Houben;P. Koeniger;J. Sültenfuss
影响因子：
1.3
作者：
Hartmann, Martin;Nielsen, Heimo
通讯作者：
Nielsen, Heimo
影响因子：
3.4
作者：
Stephan L. Seibert;T. Holt;Anja Reckhardt;J. Ahrens;M. Beck;T. Pollmann;L. Giani;Hannelore Waska;M. Böttcher;J. Greskowiak;G. Massmann
通讯作者：
Stephan L. Seibert;T. Holt;Anja Reckhardt;J. Ahrens;M. Beck;T. Pollmann;L. Giani;Hannelore Waska;M. Böttcher;J. Greskowiak;G. Massmann
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
影响因子：
1.3
作者：
M. Böttcher;Britta Hespenheide;H. Brumsack;K. Bosselmann
通讯作者：
K. Bosselmann
影响因子：
9.8
作者：
Bryan, Eliza;Meredith, Karina T.;Post, Vincent E. A.
通讯作者：
Post, Vincent E. A.