Isotopic Evidence for Determining the Sources of Dissolved Organic Sulfur in a Forested Catchment

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• 作者：Phil-Goo Kang ; Myron J. Mitchell ; Bernhard Mayer ; John L. Campbell
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：October 7, 2014
• 年：2014
• 卷：48
• 期：19
• 页码：11259-11267
• 全文大小：474K
• ISSN：1520-5851

文摘

Understanding sulfur (S) biogeochemistry, especially in those watersheds subject to elevated levels of atmospheric S inputs, is needed for determining the factors that contribute to acidification, nutrient losses and the mobilization of toxic solutes (e.g., monomeric aluminum and methylmercury). S is found in a variety of both organic and inorganic forms undergoing a range of biotic and abiotic transformations. In watersheds with decreasing atmospheric S inputs, internal cycling is becoming dominant in affecting whether there is net loss or retention of S. Little attention has been given to the role of dissolved organic S (DOS) in affecting S biogeochemistry. DOS originates from assimilatory and bacterial dissimilatory S reduction (BDSR), the latter of which produces ³⁴S-depleted S. Within groundwater of the Archer Creek Catchment in the Adirondack Mountains (New York) there was reoxidation of reduced S, which was an important source of SO₄^{2鈥?/sup>. DOS in surface waters had a higher variation of 未34S鈥揇OS values (鈭?.0 to +8.4鈥? than inorganic S with 未34S鈥揝O₄2鈥?/sup> values ranging from +1.0 to +5.8鈥? Inverse correlations between 未34S values of SO₄2鈥?/sup> and DOS suggested that BDSR played an important role in producing DOS.}