Comparison of greenhouse gas fluxes and nitrogen budgets from an ombotrophic bog in Scotland and a minerotrophic sedge fen in Finland

Northern peatlands cover approximately 4% of the global land surface area. Those peatlands will be particularly vulnerable to environmental and climate change and therefore it is important to investigate their total greenhouse gas (GHG) budgets, to determine the feedback on the climate. Nitrogen (N) is known to influence the GHG budget in particular by affecting the methane (CH(4)) balance. At two peatland sites in Scotland and Finland GHG fluxes of carbon dioxide (CO(2)), methane and nitrous oxide (N(2)O) and nitrogen fluxes were measured as part of the European project 'NitroEurope'. The Scottish site, Auchencorth Moss, was a GHG sink of -321, -490 and -321 g CO(2) eq m(-2) year(-1) in 2006, 2007 and 2008, respectively, with CO(2) as the dominating GHG. In contrast, the dominating GHG at the Finnish site, Lompolojankka, was CH(4), resulting in the site being a net GHG source of +485 and +431 g CO(2) eq m(-2) year(-1) in 2006 and 2007, respectively. Therefore. Auchencorth Moss had a negative global warming potential (GWP) whilst Lompolojankka had a positive GWP over the investigated time period. Initial results yielded a positive N budget for Lompolojankka of 7.1 kg N ha(-1) year(-1), meaning the site was gaining nitrogen, and a negative N budget for Auchencorth Moss of -2.4 kg N ha year(-1), meaning the site was losing nitrogen.