Peatland ecosystems store approximately one-third of the World's soil carbon and are located on the transition from terrestrial (generally dry) and aquatic (generally wet) ecosystems. As such, peatlands are quite sensitive to land-use (drainage, mining) and climate change (drought) and can represent a very major positive feedback to climate change. We examine this subject from an inter-disciplinary approach combining methods and knowledge in the fields of hydrology, soil science, biogeochemistry, ecology and climatology.