CIRCULATION IN THE RIBBON REEF REGION OF THE GREAT-BARRIER-REEF

Circulation within the Ribbon Reef Region of the Great Barrier Reef, Australia, is examined with a combined data set obtained from a conventional current meter, an HF radar, Landsat MSS imagery and results from a high resolution numerical circulation model. Circulation within the region is dominated by the development of a strong jet and eddy system which is established in the narrow gaps between the reefs. In contrast, little flow occurs over the reefs themselves. The eddies extend up to 10 km across the shelf and hence provide a very effective mechanism to enhance the exchange of water between the deep ocean and the Great Barrier Reef lagoon. Dispersion modelling shows that the orientation of the reefs, the reef-gap interactions and the physical size of the gaps may result in ''patchiness'' in nutrient levels landward of the reefs.