Impacts of recent anthropogenic changes on peatland carbon dynamics

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Importance of peatlands Peatlands are the most widespead group of wetlands. Their total extent has been estimated to more than 400 million km2 which represents 3-4% of the earth's surface. More than 90% of peatlands are located in the temperate and cold belt in the Northern Hemisphere (boreal and subarctic) where cool and moist conditions favor decreased rate of organic matter decomposition. Peatlands provide important ecosystem services to society. They play an important role in the global hydrological cycle helping maintain both water quantity and quality. They also play a significant role in climate regulation as they constitute important carbon sinks by storing > 40% of the total carbon in soils over the planet. International organizations have recently recognized the role of peatland ecosystems in climate attenuation and one of the major statement from the recent Global Symposium on Soil Organic Carbon in Rome (2017) has been that reduction of terrestrial carbon sink represents one of the key risk for future climate change. Role in the atmospheric carbon cycle There is currently no consensus on the direction or magnitude of the recent warming-induced changes on soil carbon. With rising surface temperatures, some recent studies have simulated a net loss of carbon to the atmosphere while some others suggest a rise of biological productivity, hence more carbon uptake linked with longer growing-seasons. Taking into account the natural and damaged conditions of peatlands in eastern Canada and following a synthesis produced for the Ministère du Développement Durable, de l'Environnement et de la Lutte contre les Changements Climatiques (MDDELCC), Québec on the quantification of peatlands carbon stocks in the Quebec province, the objectives of the proposed five years program aim to document the recent (comparison of soil organic carbon dynamics in these different bioclimatic regions and distangle the changes due to natural and anthropogenic pressures. Changes in carbon stocks and carbon accumulation due to human activities (ex. drainage) will be compared with the potential increase in biomass productivity that could potentially offset the impact of anthropogenic greenhouse gas emissions.