title: Effect of acid deposition on quantity and quality of dissolved organic matter in soil-water.
abstract: The aim of this study was to explore how acid deposition may affect the concentration and quality of dissolved organic matter (DOM) in soil-water. This was done by a small-scale acidification experiment during two years where 0.5 × 0.5 m(2) plots were artificially irrigated with water with different sulfuric acid content, and soil-water was sampled using zero-tension lysimeters under the O-horizon. The DOM was characterized using absorbance, fluorescence, and size exclusion chromatography analyses. Our results showed lower mobility of DOM in the high acid treatment. At the same time, there was a significant change in the DOM quality. Soil-water in the high acid treatment exhibited DOM that was less colored, less hydrophobic, less aromatic, and of lower molecular weight, compared to the low acid treatment. This supports the hypothesis that reduction in sulfur deposition is an important driver behind the ongoing brownification of surface waters in many regions.
authors.affiliation: Department of Biology/Aquatic Ecology, Lund University, Lund, Sweden. sara.ekstrom@biol.lu.se
authors.forename: Sara M
authors.initials: SM
authors.lastname: Ekström
authors.forename: Emma S
authors.initials: ES
authors.lastname: Kritzberg
authors.forename: Dan B
authors.initials: DB
authors.lastname: Kleja
authors.forename: Niklas
authors.initials: N
authors.lastname: Larsson
authors.forename: P Anders
authors.initials: PA
authors.lastname: Nilsson
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Graneli
authors.forename: Bo
authors.initials: B
authors.lastname: Bergkvist
mesh_terms: D015258:Acid Rain; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*
chemical_list: D015258:Acid Rain; D009930:Organic Chemicals; D012987:Soil