Suspended matter transport in coral reef waters of the Abrolhos Bank, Brazil

The coral reef system of the Abrolhos Bank, Brazil, is located between 10 and 65 km off the coast. Suspended particulate matter between the coast and the inner arc of the reef was mainly composed of kaolinite clay and reworked fossil carbonate fragments, resuspended from nearshore shoals. Strong permanent and tidal alongshore currents in the nearshore channel together with the geomorphological configuration of the inner arc formed an efficient hydrodynamic and topographic barrier to offshore transport of land-derived material. Most of the material was being transported alongshore. Suspended particulate matter between the inner and outer arcs was dominated by carbonate shells, coral fragments, and needle-shaped biogenic opal, and the reef system was in large part being dominated by the oligotrophic waters of the Brazil Current.