The environmental impact of the reverse osmosis desalination plant on the immediately surrounding water and coral reef ecosystem in Bonaire, Dutch Caribbean

One of the most promising solutions to the growing shortage of potable water is the tapping of the oceans through desalination. Until recently the high energy costs of this technology has kept it restricted to oil rich countries in the Middle East. As the need for fresh water has grown and the technology has improved, municipal desalination has slowly expanded out of this region and several plants have been built in the Caribbean and Australia, with more planned. These two regions also house some of the highest concentrations of reefs in the world, and exceedingly little research has been done on the impact of effluent from desalination plants on coral reef ecosystems. Desalination plants release hypersaline water with heightened thermal energy, lowered O2 levels, and a variety of chemical additives. This study used a modified AGRRA benthic survey method to compare coral mortality and reef composition outside the desalination plant to a control site in Bonaire, Dutch Caribbean. The LaMotte Salt Water AquaCulture Test Kit and Hanna Instruments HI 713 Phosphate Low Range kit were used to compare water samples within and between sites. The reef in close proximity to the desalination plant was found to have significantly lower live hard coral, gorgonian, and fire coral cover, and higher sand cover by percent than the control site. The reef also showed significantly higher rates of coral mortality than the control site. The water around the plant was also found to have higher salinity, but lower levels of CO2 and nitrates than the control site. These results suggest that the desalination plant has a negative effect on the surrounding coral reef ecosystem’s health and complexity. These results should give pause to governments planning the development of desalination plants near coral reef environments until more research can be done into this technology’s_environmental_impact.

This student research was retrieved from Physis: Journal of Marine Science IX (Spring 2011)19: 57-63 from CIEE Bonaire.