The Robert B. Annis Field Station houses AWRI's Mesocosm Facility. Mesocosms are experimental units (tanks) that are larger than aquariums (microcosms) but smaller than natural ponds (macrocosms). The Mesocosm Facility consists of 12 tanks that each hold 350 gallons of water.

The mesocosms are located in a climate- and light-controlled room, which dramatically increases our capability to conduct experimental research at AWRI. The first mesocosms at AWRI were located in the original un-heated field station and were not available for year-round research.

Some examples of experiments that have been conducted in AWRI's mesocosms include:

• The effect of light on the growth of phytoplankton and their ability to develop nuisance algal blooms.
• Interactions between different fish species, particularly round gobies and yellow perch.
• The genetic basis of herbicide resistance in nuisance aquatic plants.