Methane Release from Three Active Peatland Microforms and their Contribution to the Greenhouse Gas Budget of Foxtor Mires, Dartmoor

Peatlands act as both a source and sink of greenhouse gas (GHG), therefore with a changing climate it is becoming increasingly important to accurately quantify the source/sink strengths of peatlands, and understand the contribution of individual fluxes within GHG budgets. This study aimed to assess the relationship between methane (CH4) emissions and three peatland microforms; lawns, hummocks and pools at Foxtor Mires, Dartmoor. An average summer GHG budget was then to be modelled for Foxtor Mires with fluxes from net primary productivity (NPP), CH4, dissolved organic carbon (DOC) and particulate organic carbon (POC), with sub-models created for each microform. CH4 was collected in the field using the static chamber method and Fourier transform infrared spectroscopy (FTIR) was used to quantify CH4 samples. Median emission values of 12.17 mg m-2 d-1, 9.35 mg m-2 d-1 and 5.63 mg m-2d-1 were recorded at the pool, lawn and hummock microforms respectively. The number of vascular plant species was found to be the major control of differences in CH4 emissions between microforms. The average summer GHG budget for Foxtor Mires revealed it to be a sink of GHG with a net CO2e storage of 2.05 t ha-1yr-1. Sub-models of the lawn and pool microforms determined fluxes at Foxtor Mires to be in relative equilibrium with a net CO2e of +0.57 t ha- 1 yr-1 and -0.48 t ha-1 yr-1 respectively, the hummock sub-model determined Foxtor Mires to be a sink with a net CO2e of +7.09 t ha-1 yr-1. Creating sub- models highlighted the spatial variability associated with GHG fluxes and the need for sub-models for proper GHG source/sink management