title: Hydrology-driven ecosystem respiration determines the carbon balance of a boreal peatland.
abstract: The carbon (C) balance of boreal peatlands is mainly the sum of three different C fluxes: carbon dioxide (CO2), methane (CH4) and dissolved organic carbon (DOC). Intra- and inter-annual dynamics of these fluxes are differentially controlled by similar factors, such as temperature and water-table. Different climatic conditions within and between years might thus result in varying absolute and relative contributions of each flux to net ecosystem productivity (NEP). In this study CO2 fluxes were measured at a boreal peatland in eastern Finland during a dry year (2006) and a wet year (2007) and combined with DOC and CH4 fluxes from the same site. CO2 uptake in the wet year was 65% higher than in the dry year, caused by higher water table (WT) and subsequently reduced rates of soil respiration. Two to three-fold increases in DOC and CH4 fluxes in the wet year did not completely offset the higher CO2 uptake in that year, resulting in NEP of -83.7±14 g C m(-2) in the dry and -134.5±21 g C m(-2) in the wet year. Thus, in our study, WT was identified as the most important factor responsible for variations in the C balance between the observed years.
authors.affiliation: Institute of Botany and Landscape Ecology, Ernst Moritz Arndt University Greifswald, Grimmer Straße 88, 17487 Greifswald, Germany. Electronic address: michal.gazovic@gmail.com.
authors.forename: Michal
authors.initials: M
authors.lastname: Gažovič
authors.forename: Inke
authors.initials: I
authors.lastname: Forbrich
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Jager
authors.forename: Lars
authors.initials: L
authors.lastname: Kutzbach
authors.forename: Christian
authors.initials: C
authors.lastname: Wille
authors.forename: Martin
authors.initials: M
authors.lastname: Wilmking
mesh_terms: D057486:Carbon Cycle; D017753:Ecosystem; D005387:Finland; D010101:Oxygen Consumption; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D014867:Water; D014887:Weather
chemical_list: D012987:Soil; D014867:Water
keywords: Carbon cycling; Eddy covariance; Inter-annual variations