A stochastic appraisal of the annual carbon budget of a large circumborealpeatland, Rapid River Watershed, northern Minnesota

The probable limits of the carbon budget of the Rapid River Watershed, with in the greater Glacial Lake Agassiz Peatland in northern Minnesota, were ev aluated using a Monte Carlo simulation approach. Carbon enters the peatland s in groundwater, precipitation, and primary productivity. Carbon leaves th e peatlands by groundwater and surface water outflow and by the outgassing of methane. Results of the simulations of the carbon budget show that the p eatland is now probably a sink for carbon, supported by field data showing pear is, in fact, accumulating at the rate of about 1 mm yr(-1) [Glaser er al., 1997]. Excluding extreme values, Monte Carlo simulation results indica te that the Rapid River Peatland stores between -28.98 g C m(-2) yr(-1) (re lease) and 50.38 g C m(-2) yr(-1) (storage) with a mean accumulation of 12. 74 g C m(-2) yr(-1) over the 1,506,200 m(2) watershed. The peatland appears to be delicately poised with respect to net gain or loss of carbon.