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The multi-annual carbon budget of a peat-covered catchment

Worrall, F., Burt, T.P., Rowson, J.G., Warburton, J., Adamson, J.K.
Science of the total environment 2009 v.407 no.13 pp. 4084-4094
watersheds, peat soils, carbon, biogeochemical cycles, dissolved organic carbon, carbon dioxide, methane, primary productivity, carbon sinks, soil-atmosphere interactions, soil nutrient balance, temporal variation, England
This study estimates the complete carbon budget of an 11.4 km² peat-covered catchment in Northern England. The budget considers both fluvial and gaseous carbon fluxes and includes estimates of particulate organic carbon (POC); dissolved organic carbon (DOC); excess dissolved CO₂; release of methane (CH₄); net ecosystem respiration of CO₂; and uptake of CO₂ by primary productivity. All components except CH₄ were measured directly in the catchment and annual carbon budgets were calculated for the catchment between 1993 and 2005 using both extrapolation and interpolation methods. The study shows that: Over the 13 year study period the total carbon balance varied between a net sink of -20 to -91 Mg C/km²/yr. The biggest component of this budget is the uptake of carbon by primary productivity (-178 Mg C/km²/yr) and in most years the second largest component is the loss of DOC from the peat profile (+39 Mg C/km²/yr). Direct exchanges of C with the atmosphere average -89 Mg C/km²/yr in the catchment. Extrapolating the general findings of the carbon budget across all UK peatlands results in an approximate carbon balance of -1.2 Tg C/yr (±0.4 Pg C/yr) which is larger than previously reported values. Carbon budgets should always be reported with a clear statement of the techniques used and errors involved as this is significant when comparing results across studies.