The Supporting Role of Mesocosm-Scale Laboratory Experiments in Solving Critical Issues at Hydrogeological Research Sites

Hydrogeological research sites provide a unique opportunity to study parameters and processes at the field scale. However, the most successful long-term research sites have been coupled with laboratory-scale experiments and numerical modeling studies. Mesocosm-scale laboratory experiments allow the investigation of local-scale hydrogeological processes often with sensors that exceed the spatial, temporal, and accuracy of field based monitoring. After over two years of design and construction a unique mesocosm-scale hydrogeological climate chamber was emplaced at the University of Western Ontario Biotron facility in April 2008. What makes this chamber different from other ecohydrological chambers is the ability to reproduce the subarctic solar and atmospheric environment and house soil monoliths up to 1.5 m in diameter and 4 m in height. Of particular importance is the ability to subject soil monoliths, inclusive of vegetation, to climate forcing experiments (varying solar energy, air temperature, precipitation, wind, CO2) while continuously monitoring liquid, gas, and energy fluxes. At present, experiments on 60 cm diameter by 90 cm deep peat / permafrost cores from our central Mackenzie River basin long-term field site are being conducted to better elucidate moisture and carbon transport processes occurring in the active layer. These climate forcing laboratory based experiments will be closely integrated with on-going field studies in the basin. Through this research we will be able to develop a physically-based numerical model to estimate the volume and timing of runoff from wetland-dominated basins in discontinuous permafrost. The experiments will answer critical questions, not addressable by field data alone, on how subarctic ecosystems will respond to climate change. We would also like to foster collaborations to address other scientific questions utilizing the climate chamber. In particular, experiments in support of pilot scale remediation efforts in cold regions or phytoremediation studies would be ideally suited to this unique hydrogeological research facility.