Characterizing the Redox Status in Three Different Forested Wetlands with Geochemical Data

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• 作者：Christine Alewell ; Sonja Paul ; Gunnar Lischeid ; Kirsten K&uuml ; sel ; Matthias Gehre
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：December 15, 2006
• 年：2006
• 卷：40
• 期：24
• 页码：7609 - 7615
• 全文大小：197K
• 年卷期：v.40,no.24(December 15, 2006)
• ISSN：1520-5851

文摘

Biogeochemistry and regulation of redox processes inwetlands and especially their source sink functions regardingsulfur, nitrogen, iron, and alkalinity are still poorlyunderstood and become increasingly important in a worldof global change. We investigated three forested wetlandswithin the Lehstenbach catchment (Fichtelgebirge,Northeastern Bavaria, Germany) differing in their degreeof water saturation, vegetation, and availability of iron withstable sulfur analysis as well as geochemical analysis(iron, nitrate, sulfate, and oxygen contents in soil solutionsand groundwater). Results indicated considerable nitrate,sulfate, and iron reduction rates bound to high spatialand temporal heterogeneity at all three sites. Sites differedsignificantly regarding their oxygen saturation and theirdynamics of sulfur and iron reduction. The sequential reductionchain did not seem an applicable concept to describeredox dynamics at micro- (cm²) or mesoscale (m²) becauseof (1) high small-scale heterogeneity and (2) an absenceof clear relationships between redox indicative parameters.The latter might be caused by redox processes occurringsimultaneously at the investigated spatial and temporalscales. However, a tendency toward exclusive relationshipsbetween oxygen and iron, nitrate and iron, and ³⁴S withoxygen, nitrate, and sulfate indicated that the sequentialreduction chain might be a suitable modeling concept formacroscale (km²) investigations with large samplenumbers.