Coral reef mesocosms and microcosms — successes, problems, and the future of laboratory models

Four coral reef mesocosms and microcosms, all established with the same basic approach to ecological engineering, are compared and contrasted. With some modifications, all use algal turf scrubbers as the primary device for controlling water quality, and thus leave the critical planktonic component undisturbed. The uses of engineering and applied ecology/biology to control and maintain these enclosed ecosystems has influenced their character and has contributed to both problems on some systems (patch formation, reduced reproduction and loss of plankton due to conventional pumping and filtration) and solutions on others (exterior control over predation and grazing, plankton friendly pumping and filtration) related to maintaining diverse, sustaining reef populations. As highly complex models, these systems can be unique tools for research on many aspects of the biology, ecology and restoration of coral reefs and on the effects of global change. Additionally, they support the view that the fragmentation of ecosystems can significantly alter community structure and diversity.