Revisiting Large Scale Physical Models for Biogeochemical Studies

ABSTRACT: Large-scale physical models also referred to as mesocosms, such as the 2.4 m diameter x 4.6 m high cylinder at Environment Canada’s Innovation Place in Saskatoon, are of sufficient size that relevant chemical, biogeochemical processes are active and thus permitted field behavior under controlled conditions. The 4.6 m high cylinder was filled with 65 t of C-horizon sand excavated at a field site located 10 km south of Saskatoon and was monitored for seven years. Due to a lack of maintenance and application of water to the surface, the top 2 m of the soil was desiccated. Today, several institutions have set up their own large-scale physical models, and thus the 4.6 m high cylinder could have served as the basis to evaluate the performance of newer large-scale physical models. This paper revisits the CO2 fluxes measured from the 4.6 m high cylinder from day 2254 to day 2604 and a waste rock pile at the Key Lake uranium mine from 2000 to 2002, using the dynamic closed chamber system DCC.