The Experimental Mesocosm Facility (EMF) is a 4400 square foot glasshouse separated into 8 rooms. Located on the roof of the annex of the Tom Bevill Energy, Mineral and Materials Science Research Building, the facility contains 18 large 7-cubic meter artificial systems that permit simulation of either wetland or lotic environments. The facility has controlled lighting (halogen and sodium PAR spectra) in each room allowing replication of growth conditions and extension of photoperiod to circumvent winter dormancy. Water temperature in each of the 18 artificial systems is individually controlled, and physical conditions within each chamber, such as water temperature, air temperature, light intensity and stage are continuously recorded using Campbell Scientific, Inc. CR-10 dataloggers. These mesocosms contain either stream or wetland flora, fauna, and microbial communities transplanted into sediments and water that have been imported from research sites. Water is circulated through each mesocosm by paddle wheels at rates replicating the slow flows of wetlands or the faster velocities typical of stream environments. Evaporative water losses are replenished daily with distilled water.