Carbon accumulation in peat deposits from northern Sweden to northern Germany during the last millennium

Historic carbon accumulation rates in four bogs on a north to south transect from Sweden to Germany were calculated by using the bulk densities and carbon concentrations of 1-cm peat layers and a fine-resolution radiocarbon chronology. Carbon accumulation rates were compared to environmental data to explore the effects of climatic factors. Carbon accumulation rates in a period without clear human impact on the bog ecosystems (c. ad 1700-ad 1800) ranged from 25 g C/m2/yr in the most northern site to 50 g C/m2/yr in the southernmost site, which coincided with increasing annual temperatures from north to south. This suggests that temperature or growing season length is a major factor influencing carbon accumulation rates at different geographical sites. The temporal variations in carbon accumulation rates within the sites tentatively suggest that carbon accumulation rates may still increase with further warming in northern peat bogs, but decrease in southern peat bogs.