PARENT SESSION
Contributed Oral Session 155: Biogeochemistry: Soil Carbon Dynamics
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 516 A, Level 5, Palais des congrès de Montréal
Carbon dynamics in a northern peatland: Source or sink?
Ward, Susan *,1, 2, McNamara, Niall1, Ostle, Nick1, Bardgett, Richard2, 1 Centre for Ecology and Hydrology (CEH), Lancaster, UK2 Lancaster University, Lancaster, UK
ABSTRACT- Peatland ecosystems represent a vast global carbon sink, due to low rates of decomposition in a cold, waterlogged, and nutrient poor environment. On a worldwide scale, the build up of deep layers of peat has resulted in northern peatlands becoming substantial terrestrial carbon stores, accounting for approximately one third of the global pool. However, recent changes in climate, and in anthropogenic activities affecting land use, have the potential to alter decomposition processes in these ecosystems. This could potentially destabilise carbon stores, leading to a switch from a carbon sink to source, with subsequent changes to the balance of short term global carbon cycling and climate change feedback mechanisms. The main aim of our research is to obtain a greater understanding of the factors controlling carbon release from peatlands. We looked at present day carbon dynamics, both above and below ground, in a managed moorland ecosystem in northern England. We measured seasonal and diurnal trace gas fluxes of CO2 and CH4 under different burning and grazing regimes, alongside measures of soil microbial dynamics, vegetation species composition and soil water chemistry. Results show that although carbon release is primarily controlled by climate, biotic factors relating to soil and vegetation also have an effect. More specifically, burning alters soil and vegetation carbon and nitrogen pools, resulting in increased respiration and photosynthesis. These data are being used to predict future carbon release from peatlands in the light of changing climate and land use.
Key words: Carbon, Peatland, Climate Change