Final Activity Report Summary - EHAWC (European high arctic wetland change)
Peat cores and surface samples were collected in 2007 and 2008 at several low-elevation sites from the inner fjords of west-central Spitsbergen between 78 and 79N. Decadally-resolved indicators of peat decomposition together with high-resolution carbon assays and radiocarbon dating reveal that Arctic mires in Svalbard are highly sensitive to perturbation. Patterns in the rate of carbon accumulation included abrupt slowdowns/near-shutdowns of carbon accumulation that have persisted for centuries to surprisingly high sustained rates - as high as Eurasian sites much further south.
For example, 6000-year old organic deposits at 79N show slowdown in carbon sequestration contemporaneous with the close of Holocene Thermal Maximum conditions, whereas, 1500-year-old deposits at 78N show renewed sequestration around AD 1500 following a multi-centennial hiatus. This highly-sensitive carbon sequestration response to past warming was shown to be strongly mediated by hydrological conditions, suggesting that future response in a warmer Arctic will have a strong reliance on the fate of local water and changes in the amount and seasonality of precipitation.