title: Effect of inundation, oxygen and temperature on carbon mineralization in boreal ecosystems.
abstract: The inundation of boreal forests and peatlands through the construction of hydroelectric reservoirs can increase carbon dioxide (CO2) and methane (CH4) emission. To establish controls on emission rates, we incubated samples of forest and peat soils, spruce litter, forest litter and peatland litter collected from boreal ecosystems in northern Quebec for 16 weeks and measured CO2 and CH4 production rates under flooded or non-flooded conditions and varying oxygen concentration and temperature. CO2 production under flooded conditions was less than under non-flooded conditions (5-71 vs. 5-85 mg Cg(-1) C), but CH4 production under flooded conditions was larger than under non-flooded conditions (1-8158 vs. 0-86 μg Cg(-1) C). The average CO2 and CH4 production rate factor for flooded:non-flooded conditions was 0.76 and 1.32, respectively. Under flooded conditions, high oxygen concentrations increased CO2 production in peat soils but decreased CH4 production in forest and peat soils and spruce litter. Warmer temperatures (from 4 to 22°C) raised both CO2 production in peat soils and peatland litter, and CH4 production in peat soils and spruce litter. This study shows that the direction and/or strength of CO2 and CH4 fluxes change once boreal forests and peatlands are inundated.
authors.affiliation: Department of Geography, McGill University, Montreal, QC H3A 0B9, Canada; Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA. Electronic address: youngil.kim@oregonstate.edu.
authors.forename: Youngil
authors.initials: Y
authors.lastname: Kim
authors.affiliation: School of Physical and Geographical Sciences, Keele University, Staffordshire ST5 5BG, UK. Electronic address: s.ullah@keele.ac.uk.
authors.forename: Sami
authors.initials: S
authors.lastname: Ullah
authors.affiliation: Department of Geography, McGill University, Montreal, QC H3A 0B9, Canada. Electronic address: nigel.roulet@mcgill.ca.
authors.forename: Nigel T
authors.initials: NT
authors.lastname: Roulet
authors.affiliation: Department of Geography, McGill University, Montreal, QC H3A 0B9, Canada. Electronic address: tim.moore@mcgill.ca.
authors.forename: Tim R
authors.initials: TR
authors.lastname: Moore
keywords: Boreal forests; Carbon dioxide production; Flooding; Methane production; Oxygen concentration; Peatlands; Temperature