ABSTRACT
Seawater desalination using reverse osmosis technology is being investigated as a potential alternative source of potable water in southwest Florida. Although the technology for desalinating brackish groundwater and/or seawater is well established, questions remain concerning the effects of reverse osmosis seawater desalination discharges, i.e., brine. This study examined the response of a meadow of turtle grass
Thalassia testudinum
to the direct discharge of brine from a desalination plant in Antigua, West Indies. Shoot density, areal blade biomass, and areal blade productivity were determined prior to, and then 3 and 6.5 months after, the diversion of a discharge plume onto a previously unimpacted turtle grass meadow. No relationship was found between temporal changes in density, biomass, or productivity, and the degree of exposure to brine discharge as quantified by the change in salinity vs. background values. After 3 months of discharge diversion, a weak yet statistically significant relationship was detected between macroalgal biomass and degree of exposure to brine discharge. The increased macroalgal abundance is believed to be caused by increased availability of nitrogen in the discharge plume. This is most likely due to episodic loading from backflushing of filters, incidental releases of detergents used to eliminate bio-fouling, and combined stormwater discharges.
