title: Effects of canopy-deposition interaction on H+ supply to soils in Pinus banksiana and Populus tremuloides ecosystems in the Athabasca oil sands region in Alberta, Canada.
abstract: Soil acidification has been of concern in the oil sands region in Alberta due to increased acid deposition. Using the canopy budget model, and accounting for H(+) canopy leaching by organic acids, we determined sources and sinks of H+ in throughfall in jack pine (Pinus banksiana) and trembling aspen (Populus tremuloides) stands in two watersheds from 2006 to 2009. In pine stands, H+ deposition was greater in throughfall than in bulk precipitation while the opposite was true in aspen stands. The annual H+ interception deposition was 148.8-193.8 and 49.7-70.0 molcha(-1) in pine and aspen stands, respectively; while the annual H+ canopy leaching was 127.1-128.7 and 0.0-6.0 molcha(-1), respectively. The greater H+ supply in pine stands was caused by greater interception deposition of SO4(2-) and organic acids released from the pine canopy. Such findings have significant implications for establishing critical loads for various ecosystems in the oil sands region.
authors.affiliation: Department of Renewable Resources, 442 Earth Sciences Building, University of Alberta, Edmonton, Alberta, Canada T6G 2E3. kangho@ualberta.ca
authors.forename: Kangho
authors.initials: K
authors.lastname: Jung
authors.forename: Scott X
authors.initials: SX
authors.lastname: Chang
authors.forename: M A Charlie
authors.initials: MA
authors.lastname: Arshad
mesh_terms: D015258:Acid Rain / Q000032:analysis*; D000416:Alberta; D002264:Carboxylic Acids / Q000737:chemistry; D017753:Ecosystem; D019652:Extraction and Processing Industry; D006863:Hydrogen-Ion Concentration; D028223:Pinus / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D032107:Populus / Q000737:chemistry*; D012987:Soil / Q000032:analysis*
chemical_list: D015258:Acid Rain; D002264:Carboxylic Acids; D012987:Soil