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Title: Carbon emissions from managed upland peat
Author: Rowson, James Graham
ISNI:       0000 0001 3538 8760
Awarding Body: Durham University
Current Institution: Durham University
Date of Award: 2008
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Upland peat is the world's largest store of soil carbon and one of the most climatically sensitive. Concerns have been raised about the stability of the carbon within these stores and how upland peat will respond to climate change. Climate change is predicted to increase average, ~axirnum and minimum temperatures and also reduce summer rainfall in the UK. This predicted change in climate is hypothesised to reduce water table depth and increase soil respiration in upland peat causing upland peat to, potentially, turn from a net sink of carbon into a carbon net source. A range of management practises have been and are being carried out in the UK uplands, often with the view to increase grazing density or increase other commercial animal species such as grouse. This qualifies peat as grazed land under the ratified Kyoto protocol, and any demonstrated increase in carbon storage potential can be used to offset carbon emissions from the UK. Therefore, questions have been raised as to the best management practises for carbon storage potential. By demonstrating that restoration of water table depths in upland peat will reduce CO2 emissions sufficiently above the corresponding increase in CHt emissions associated with water table rise, .carbon stores can be stabilised and the carbon storage rate potentially increased. This thesis reports the results from a study of C02, both gaseous and dissolved, and CHt fluxes across a differential water table, allowing the results to .be analysed both spatially and temporally. From these results a model was constructed from literature and observations, considering dissolved and gaseous CO2as being produced by a single mechanism from within soil processes, where hydrological functions, such as rainfall to determine the endpoint for CO2. The model was used to analyse for the lowest level of monitoring that still gives a good estimate of the carbon budget for the field site by using mass balance equations from hydrological literature. To determine whether the model was valid for higher temperatures and lower water table depths, as predicted for climate change, a series of deep peat cores were sampled from the same site as the spatial and temporal study of CO2flux and moved to a warmer and drier site. When C02 data, measured from the peat cores, was compared to the spatial and temporal CO2fluxes a visual correlation was found between gross C02 flux for the two data sets, however upon statistical analysis it was shown that the data sets were incomparable for gross, net and primary productivity fluxes. Closed chamber measurements of CO2 flux from the spatial and temporal study were compared to eddy covariance measures of CO2flux. It was found that short term (hourly/daily) were poorly correlated whilst longer term (weekly - monthly) fluxes were better correlated. By studying a peatland on the boundary of peats temperature tolerance, this study can be applied to other peatlands to proved a model of expected responses to climate change for peat both in the UK and around the world.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available