Dissolved organic carbon (DOC) management in peatlands

Abstract

Peatlands are serving as one of the most important terrestrial carbon stores in the United Kingdom and globally. In the UK, the current trend of peatlands turning from carbon sinks to carbon sources is widely observed and reported. As numerous factors may affect the carbon cycle of peatlands, including climate, land management, hydrology and vegetation, dissolved organic carbon (DOC) was commonly used as an indicator of peatland carbon changes. Besides the function as an indicator of carbon turnover in peatland, increasing DOC in the stream water also raises concern in water companies as the removal of DOC from water represents a major cost of water treatment.
This thesis investigates the impacts of land management such as drain blocking and revegetation on stream DOC changes. By building a pilot column study, this thesis also assessed the potential of bank filtration serving as DOC treatment in UK.
Results of drain blocking shows the management was a significant impact on the DOC changes. However, later investigation of peak flow events indicates such positive impacts from drain blocking were minor in terms of high peak flow events. Since the majority of DOC export occurred during such peak flow events, drain blocking were found not as an efficient management of DOC changes. The field study of revegetation observed minor effects of revegetation on stream DOC. The results of column bank filtration indicate low DOC removal rate under the current stream DOC level in UK. The bank filtration may efficient remove DOC when higher DOC input applied. However, it is not suitable for UK peatland under current DOC export.