Peatland carbon production and transport: the role of the riparian zone

Leith, Fraser; Dinsmore, Kerry; Billett, Michael; Heal, Kate. 2012 Peatland carbon production and transport: the role of the riparian zone. In: Fernandez, Ivan J.; Norton, Stephen A.; Wilson, Tiffany, (eds.) The 7th International Symposium on Ecosystem Behavior: Conference Program and Abstracts. University of Maine, 153.

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Abstract/Summary

Northern peatlands are an important carbon store in which the carbon cycling is intrinsically linked to hydrological state. Changes in climate and land management can alter the hydrology of peatlands, with artificial drainage (and its subsequent remediation) a significant driver of hydrochemical change across UK peatlands. With fluxes associated with the aquatic pathway (Particulate Organic Carbon (POC), Dissolved Organic Carbon (DOC)), and dissolved CO2 and CH4) representing ~30% of Net Ecosystem Exchange (NEE) (Dinsmore et al. 2010), changes in peatland hydrology have the potential to significantly alter catchment carbon balances. Riparian soils occur in a key transition zone between the peatland and the stream, and have the potential to modify carbon transport pathways (Lyon et al. 2011), while being a hotspot for CH4 emissions (Dinsmore et al. 2009). It is therefore important at the catchment scale despite its limited spatial extent. This research aims to investigate the production, retention, transformation and transport of aquatic carbon species within the riparian zone. Instrumented nested piezometers have been installed in a peatland-riparian zone-stream transect of an ombrotrophic peatland near Edinburgh, UK. The experimental setup is replicated in a shallow peat site (~0.5 m peat depth) and a deeper peat site (~2 m depth) with piezometers installed at two depths corresponding to the surface and subsurface soils. At these sites a range of hydrochemical parameters (electrical conductivity, pH, temperature, water table and stream height) are combined with continuous CO2 measurements using Vaisala© non-dispersive infra-red (NDIR) sensors, weekly headspace measurements of dissolved CO2 and CH4 and water samples analysed for POC, DOC and DIC in both the piezometers and the stream. This setup provides high temporal resolution data to investigate diurnal cycling and storm event scale processes which are often shorter than routine weekly sampling would allow. Measurements are being made for at least 12 months to allow seasonal effects to be investigated under a wide range of hydrological conditions. This study is unique in its deployment of multiple NDIR CO2 sensors across the peat-stream interface. The results of 12 months monitoring will be presented and linked with carbon concentration-discharge relationships. These measurements will also be combined with hydrological tracer experiments to investigate flow paths through the riparian zone. Overall this study aims to provide new insights into both the hydrological and biogeochemical processes occurring in peatland riparian zones and to assess their importance for peatland carbon budgets. Dinsmore, K.J., Skiba, U.M., Billett, M.F., Rees, R.M. & Drewer, J., 2009. Spatial and temporal variability in CH4 and N2O fluxes from a Scottish ombrotrophic peatland: Implications for modelling and up-scaling. Soil Biology and Biochemistry 41(6): 1315-1323. Dinsmore, K.J., Billett, M.F., Skiba, U.M., Rees, R.M., Drewer, J & Helftner, C., 2010. Role of the aquatic pathway in the carbon and greenhouse gas budgets of a peatland catchment. Global Change Biology 16(10): 2750-2762. Lyon, S.W., Grabs, T., Laudon, H., Bishop, K.H. & Seibert, J., 2011. Variability of groundwater levels and total organic carbon in the riparian zone of a boreal catchment. J. Geophys. Res 116(G1): G01020.

Item Type:	Publication - Book Section
Programmes:	CEH Topics & Objectives 2009 - 2012 > Biogeochemistry
UKCEH and CEH Sections/Science Areas:	Billett (to November 2013)
ISBN:	9780877231080
Additional Keywords:	riparian zone, peatlands, carbon
NORA Subject Terms:	Ecology and Environment
Date made live:	22 Apr 2014 09:18 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/506187

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