title: Antecedent conditions control carbon loss and downstream water quality from shallow, damaged peatlands.
abstract: Losses of dissolved organic carbon (DOC) from drained peatlands are of concern, due to the effects this has on the delivery of ecosystem services, and especially on the long-term store of carbon and the provision of drinking water. Most studies have looked at the effect of drainage in deep peat; comparatively, little is known about the behaviour of shallow, climatically marginal peatlands. This study examines water quality (DOC, Abs(400), pH, E4/E6 and C/C) during rainfall events from such environments in the south west UK, in order to both quantify DOC losses, and understand their potential for restoration. Water samples were taken over a 19 month period from a range of drains within two different experimental catchments in Exmoor National Park; data were analysed on an event basis. DOC concentrations ranging between 4 and 21 mg L(-1) are substantially lower than measurements in deep peat, but remain problematic for the water treatment process. Dryness plays a critical role in controlling DOC concentrations and water quality, as observed through spatial and seasonal differences. Long-term changes in depth to water table (30 days before the event) are likely to impact on DOC production, whereas discharge becomes the main control over DOC transport at the time scale of the rainfall/runoff event. The role of temperature during events is attributed to an increase in the diffusion of DOC, and therefore its transport. Humification ratios (E4/E6) consistently below 5 indicate a predominance of complex humic acids, but increased decomposition during warmer summer months leads to a comparatively higher losses of fulvic acids. This work represents a significant contribution to the scientific understanding of the behaviour and functioning of shallow damaged peatlands in climatically marginal locations. The findings also provide a sound baseline knowledge to support research into the effects of landscape restoration in the future.
authors.affiliation: Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, United Kingdom. Electronic address: e.grand-clement@exeter.ac.uk.
authors.forename: E
authors.initials: E
authors.lastname: Grand-Clement
authors.affiliation: Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, United Kingdom. Electronic address: D.J.Luscombe@exeter.ac.uk.
authors.forename: D J
authors.initials: DJ
authors.lastname: Luscombe
authors.affiliation: Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9FE, United Kingdom. Electronic address: karen.anderson@exeter.ac.uk.
authors.forename: K
authors.initials: K
authors.lastname: Anderson
authors.affiliation: Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, United Kingdom. Electronic address: nrl203@exeter.ac.uk.
authors.forename: N
authors.initials: N
authors.lastname: Gatis
authors.affiliation: Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, United Kingdom. Electronic address: P.Benaud@exeter.ac.uk.
authors.forename: P
authors.initials: P
authors.lastname: Benaud
authors.affiliation: Geography, College of Life and Environmental Sciences, Amory Building, Rennes Drive, Exeter, Devon EX4 4RJ, United Kingdom. Electronic address: r.e.brazier@exeter.ac.uk.
authors.forename: R E
authors.initials: RE
authors.lastname: Brazier
mesh_terms: D002244:Carbon / Q000032:analysis*; D057965:Carbon Sequestration; D004784:Environmental Monitoring; D006812:Humic Substances / Q000032:analysis; D012987:Soil; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D053833:Wetlands
chemical_list: D006812:Humic Substances; D012987:Soil; D014874:Water Pollutants, Chemical; D002244:Carbon
keywords: DOC; Drainage; Drought; E4/E6; Exmoor; Water quality