Differences in redox potential in peatlands under different drainage regimes.

Reduction-oxidation (redox) reactions are central to the adsorption and release of carbon andnutrients in all soils. Different electron acceptors are used by microbes to gain energyaccording to their availability and ease of use. The presence and status of different electronacceptors and donors affects the availability of electrons in the soil. The redox conditions insoils can be described by the electric potential compared to a standard hydrogenelectrode. Recent developments in measurement methods have enabled continuous fieldmeasurements of redox potential. As redox reactions are key to carbon dioxide (CO2) andmethane (CH4) emissions and the release of phosphorus (P) and dissolved organiccarbon (DOC) from peat soils, the redox state of peatlands could be used to improvemodels that predict the functioning of these ecosystems under different water tableregimes. We present results from a redox measurement campaign of two years at the Lakkasuomire in southern Finland. The measurements were conducted at a mesotrophic site with threedifferent drainage regimes: pristine, short-term drainage and long-term drainage. At the site,also WTL, rainfall, air and soil temperature and other environmental variables aremeasured. Initial analysis shows that short- and long term drainage results in a more stable redoxregime in the surface layer (5 cm depth) and that long-term drainage results in a higher redoxpotential at 15 cm depth. In the pristime state, conditions are highly reducing most of the timealready at 15 cm depth. [ABSTRACT FROM AUTHOR]