Peatlands are one of the largest terrestrial stores of carbon. Carbon exchange in peatlands is often assessed solely by measurement of contemporary fluxes; however, these fluxes frequently indicate a much stronger sink strength than that measured by the rate of C accumulation in the peat profile over longer timescales. Here we compare profile-based measurements of C accumulation with the published net ecosystem C balance for the largest peatland area in Britain, the Flow Country of northern Scotland. We estimate the long-term rate of C accumulation to be 15.4 g C m−2 yr−1 for a site where a recent eddy covariance study has suggested contemporary C uptake more than six times greater (99.37 g C m−2 yr−1). Our estimate is supported by two further long-term C accumulation records from nearby sites which give comparable results. We demonstrate that a strong contemporary C sink strength may not equate to a strong long-term sink and explore reasons for this disparity. We recommend that contemporary C sequestration should be viewed in the context of the long-term ecological drivers, such as fires, ecohydrological feedbacks and the changing quality of litter inputs.
- climate change
- Carbon cycle