How does nitrogen and ozone deposition influence greenhouse gas fluxes in temperate peatland?

On a global scale, peatlands represent vast C-­stores as a result of the anoxic and waterlogged conditions fundamental to their formation. However, they can also be a source of CO2, in addition other greenhouse gases such as CH4 and N2O. Peatlands are highly sensitive to environmental changes, which in turn can offset the balance of their functionality in regards to climate change. Increased pollution has lead to enhanced deposition of both tropospheric ozone (O3) and nitrogen (N), and as a result of peatlands sensitive characteristics, this could have major implications for their future sustainability. This means that it is of high importance to fully understand the processes and drivers that can alter their function. This study used a temperate bog, in the Scottish Borders, aimed to manipulate enhanced O3 and N (NH3) deposition to allow for an investigation into the interactions between the greenhouse gas fluxes. It was found, on the O3 transect within this study, that the overall fluxes of all three GHGs were positive, i.e. the gases were being emitted to the atmosphere. The overall mean flux for CO2, CH4 and N2O was 0.25 mg m-­2 hour-­1, 0.12 μg m-­2 hour-­1 and 0.03 μg m-­2 hour-­1 respectively. The main drivers for both the CO2 and N2O the fluxes was temperature, although CH4 did not exhibit any significant relationships with any of the environmental variables. There were contrasting results from the NH3 transect which showed an overall uptake in CO2, although the emissions of CH4 and N2O remained positive and were higher than those found on the O3 transect. From the results, it was clear that there was an effect of enhanced NH3 on the balance of the GHGs, N2O in particular was affected on both transects. Although this study was unable to explore the effects of enhanced O3 deposition, it has produced important background data for any future studies that wish to explore the effects of increased exposure to this pollutant. In addition, it was seen that there was interaction between the NH3 and some of the gas chambers on the O3 transect, which means that studies could further explore the combination effects between the two transects.