title: Regional variation in the biogeochemical and physical characteristics of natural peatland pools.
abstract: Natural open-water pools are a common feature of northern peatlands and are known to be an important source of atmospheric methane (CH4). Pool environmental variables, particularly water chemistry, vegetation community and physical characteristics, have the potential to exert strong controls on carbon cycling in pools. A total of 66 peatland pools were studied across three regions of the UK (northern Scotland, south-west Scotland, and Northern Ireland). We found that within-region variability of pool water chemistry was low; however, for many pool variables measured there were significant differences between regions. PCA analysis showed that pools in SW Scotland were strongly associated with greater vegetative cover and shallower water depth which is likely to increase dissolved organic carbon (DOC) mineralisation rates, whereas pools in N Scotland were more open and deeper. Pool water DOC, particulate organic carbon and dissolved CH4 concentrations were significantly different between regions. Pools in Northern Ireland had the highest concentrations of DOC (mean=14.5 mg L(-1)) and CH4 (mean=20.6 μg C L(-1)). Chloride and sulphate concentrations were significantly higher in the pools in N Scotland (mean values 26.3 and 2.40 mg L(-1), respectively) than elsewhere, due to a stronger marine influence. The ratio of UV absorbance at 465 nm to absorbance at 665 nm for pools in Northern Ireland indicated that DOC was sourced from poorly humified peat, potentially increasing the bioavailability and mineralisation of organic carbon in pools compared to the pools elsewhere. This study, which specifically aims to address a lack of basic biogeochemical knowledge about pool water chemistry, clearly shows that peatland pools are highly regionally variable. This is likely to be a reflection of significant regional-scale differences in peatland C cycling.
authors.affiliation: water@leeds, School of Geography, University of Leeds, LS2 9JT, UK. Electronic address: t.e.turner@leeds.ac.uk.
authors.forename: T Edward
authors.initials: TE
authors.lastname: Turner
authors.affiliation: Biological and Environmental Sciences, University of Stirling, FK9 4LA, UK.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Billett
authors.affiliation: water@leeds, School of Geography, University of Leeds, LS2 9JT, UK.
authors.forename: Andy J
authors.initials: AJ
authors.lastname: Baird
authors.affiliation: water@leeds, School of Geography, University of Leeds, LS2 9JT, UK.
authors.forename: Pippa J
authors.initials: PJ
authors.lastname: Chapman
authors.affiliation: Centre for Ecology and Hydrology, Penicuik, Scotland, UK.
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Dinsmore
authors.affiliation: water@leeds, School of Geography, University of Leeds, LS2 9JT, UK.
authors.forename: Joseph
authors.initials: J
authors.lastname: Holden
mesh_terms: D057486:Carbon Cycle; D004784:Environmental Monitoring; D009660:Northern Ireland; D012606:Scotland; D012987:Soil; D053833:Wetlands
chemical_list: D012987:Soil
keywords: Biogeochemistry; Carbon; DOC; Peatlands; Pools; Spatial distribution; Water chemistry