Fourteen Year Carbon Balance For A Raised Temperate Bog

English Abstract:

Continuous eddy flux measurements of water, energy and CO₂, and the export of dissolved organic carbon (DOC) have been made since May 1, 1998 on a raised, ombrogenic, oligotrophic, shrub and Sphagnum covered bog, the Mer Bleue peatland, near Ottawa, Ontario, Canada. Measurements of the CH₄ flux have also been made from 1998 to the present time using a combination of manual and automated chambers, and eddy covariance. In 2007 we published a six-year (1999-2006) net ecosystem carbon balance (NECB) for Mer Bleue of ~20 ± 40 g C m^-2 yr^-1. The average NEE was ~40 g C m^-2 yr^-1 over this period and the net loss of C via the CH₄ and DOC fluxes were 4 and 15 g C m^-2 yr^-1, respectively. The six-year average NECB was remarkably similar to the long-term C accumulation rate, estimated from peat cores, for the last 3,000 years. The post 2006 NEE at Mer Bleue has increased to an average of ~60 g C m^-2 yr^-1. The loss of C via DOC and CH₄, while showing considerable year-to-year variable, has not been significantly different post 2006 than it was in the first six years. Hence, the proportional loss of C as CH₄ and DOC was slightly less post 2006 than it was before 2006. As a result the NECB has increased to ~ 80 g C m^-2 yr^-1 post 2006 yielding a 14 year contemporary NECB that is ~50% greater than the long-term accumulation rate of C.