EFFECT OF TEMPERATURE ON PRODUCTION OF CH4 AND CO2 FROM PEAT IN A NATURAL AND FLOODED BOREAL FOREST WETLAND

Flooding of a small boreal forest wetland (979) in northwestern Ontari o, caused the formation of peat islands, which resulted in an approxim ate 10 degrees C increase in peat temperatures at a depth of 50 cm. Fe at collected from the flooded wetland and a natural unflooded wetland was incubated anaerobically at temperatures of 4 degrees C, 15 degrees C, and 20 to 25 degrees C. Flooding of the wetland greatly increased CH4 production rates by increasing the ratio of CH4 : CO2 produced fro m 979 peat (40% : 60%) compared to 632 peat (20% : 80%), at both prefl ood and postflood temperatures, likely due to the altered hydrological and geochemical conditions within the peat mats due to flooding. CH4 and CO2 production rates approximately tripled for every 10 degrees C temperature increase and may have been linked to to the metabolic rate of the methanogens or the fermenters independent of the substrate qua lity. Methane production rates from deep peat deposits within the isla nds were also significant and responded well to temperature increases despite peat C-14 ages of 1000 years. Due to the large quantity of car bon stored within natural wetlands, artificial reservoirs may act as a significant and long term source of CH4 to the atmosphere.