The demise of the fringing coral reefs of Barbados and of regions in the Great Barrier Reef (GBR) lagoon - impacts of eutrophication

Abstract

Historical data from Barbados demonstrate a close correspondence between the demise of the coral reefs with increased tourist and industrial development and the resulting degradation in water quality and associated eutrophication. Chronic low levels of eutrophication can restrict coral growth and reproduction and in doing so inhibit the recovery of damaged reefs. The virtual extinction of Acropora palmata in recent times indicates that it could be particularly sensitive to eutrophication. Data suggest a eutrophication threshold of 0.3 mg chlorophyll a m if the demise of A. palmata is relevant which is low in comparison with the 0.5 mg chlorophyll a m previously suggested for the Great Barrier Reef (GBR) lagoon. Data for the lagoon off Townsville show that the status of eutrophication or fertility of the waters is equivalent to or greater than that which was associated with the demise of reefs in Barbados and Hawaii. The fertility (as measured by total diatom counts) of the lagoon water near to Low Isles is far higher than that measured in 1928-29. The increased fertility in both GBR regions is attributed mainly to agricultural runoff. -from Author