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

• Published in: Environmental science & technology Vol. 48; no. 19; pp. 11259 - 11267
• Main Authors: Kang, Phil-Goo, Mitchell, Myron J, Mayer, Bernhard, Campbell, John L
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07.10.2014
• Subjects: acidification; Adirondacks; aluminum; Biogeochemistry; Correlation analysis; Earth sciences; Earth, ocean, space; Exact sciences and technology; forested watersheds; Geochemistry; Groundwater; Groundwater - analysis; Groundwater - chemistry; Inverse problems; Isotopes; methylmercury compounds; Mineralogy; New York; Silicates; solutes; stable isotopes; streams; Sulfates - analysis; Sulfur; Sulfur - analysis; surface water; toxicity; Water geochemistry; Water Pollutants, Chemical - analysis; Watersheds; New York; United States; Adirondack Mountains; United States > US; USA, New York, Adirondack Mts; USA, New York; ANW, USA, New York; Adirondacks; Microbial activity; Isotopic analysis; Sulfur compounds; stable isotopes; biogeochemical cycle; Sulfur 34; ground water; Sulfur cycle; sulfates; North America; surface water; drainage basins; forest soils; Dissolved organic matter; hydrochemistry; soils
• ISSN: 0013-936X; 1520-5851; 1520-5851
• DOI: 10.1021/es502563n

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–. DOS in surface waters had a higher variation of δ34S–DOS values (−6.0 to +8.4‰) than inorganic S with δ34S–SO4 2– values ranging from +1.0 to +5.8‰. Inverse correlations between δ34S values of SO4 2– and DOS suggested that BDSR played an important role in producing DOS.