Disentangling long-term and short-term temperature response of carbon fluxes in a subarctic grassland ecosystem exposed to long-term, geothermal warming 

作者：Linsey Marie Avila, Bjarni D. Sigurðsson, Jesper Riis Christiansen, Klaus Steenberg Larsen · 年份：2022 · DOI：10.5194/egusphere-egu22-11645 · 研究领域：Climate change and permafrost、Geology and Paleoclimatology Research、Atmospheric and Environmental Gas Dynamics

<p>The impact of rising global temperatures on carbon cycling in some of our most sensitive ecosystems, such as the Arctic, is critical yet challenging to quantify because short- and long-term effects of warming may be different. The observed short-term temperature response of soil organic carbon (SOC) decomposition may be altered in the long-term due to changes in substrate availability and possible acclimation of soil communities. </p><p>Testing how the temperature response of soil decomposition changes over time with warming under open-air, field-scale conditions presents another obstacle for researchers, as warming experiments at different temperatures and over long measurement periods are expensive and rare. Fortunately, the ForHot grassland site in Iceland has provided us with a unique opportunity to explore soil warming effects by measuring along a naturally occurring geothermal gradient that resulted from an earthquake back in 2008.</p><p>As part of the FutureArctic project at the ForHot site, we collected five replicate soil cores to a soil depth of 5 cm (100cm3 per sample), from fourteen plots along the geothermal gradient spanning a soil warming gradient from 0°C to +80°C. The samples were incubated in the lab at 5, 15, 25, and 35°C, and flux rates of CO2 and CH4 were measured using a LGR-ICOS M-GGA-918 to produce observational Q10 temperature r...