Peatland Dissolved Organic Carbon Export to Surface Waters: Global Significance and Effects of Anthropogenic Disturbance

Abstract Peatlands are key components of the global carbon cycle. We compiled peatland dissolved organic carbon (DOC) export from 62 sites to provide a global estimate of the contribution of these ecosystems to fluvial organic carbon fluxes. Despite their modest coverage on land (less than 3%), peatlands contribute at least 91 ± 54 Tg DOC to surface waters, and could represent from 12% to 20% of the DOC ultimately transferred to oceans. Boreal peatlands are the main contributors, with 58% of peatland inputs. Tropical peatlands contribute 37% of global peatland fluxes although representing only 13% of global peatland areas. Temperature is the leading factor explaining the variability in DOC fluxes for natural sites, when it is discharge for sites impacted by direct anthropogenic activities. This suggests different trajectories under climate change pressure for non–disturbed and disturbed sites and reinforces the need for hydrological restoration of disturbed peatland sites worldwide.