Achievement

Arctic soils store twice as much C as the atmosphere; permafrost thaw could radically alter global C cycling. This interdisciplinary I-WATER project assessed changes in biological and chemical reactivity induced by warming by studying permafrost cores from Sagwon Hills, Alaska. CO2 respiration rates were depressed, but did not completely cease under anoxic conditions and low temperatures, and increased with oxygen availability and temperature. Release of CH4 was highest several days after incubation, possibly resulting from soil-matrix degassing. Iron availability and potential extracellular enzyme activities did not show a distinguishable trend but may be explained by changes in carbon chemistry using Fourier transform infrared spectroscopy and emission excitation matrices. Our preliminary results indicate Arctic soils are vulnerable to chemical and biological transformation induced by warming, and could significantly impact global C cycling.