Mapping facial cavities on a lagoonal patch reef on Davies Reef, Great Barrier Reef

Systematic description of the surface character of the various reefal elements of lagoonal patch reefs is necessary to help resolve questions in regard to nutrient flow and general trophodynamics within these systems. Davies Reef, east of Townsville, was chosen as a study site to gather relevant background information. Davies Reef consists of a south-easterly aspect, curved (kidney-shaped) coral barrier enclosing a shallow (about 10m deep) lagoon with many patch reefs (bommies), about 50m in diameter. A single, relatively small bommie (1) general size and shape of cavities or depressions of the bommie walls and2) some indication of the biotic make-up on the bommie wall and immediately adjacent. On the basis of this survey, a study to determine the characteristics of nutrient concentrations in waters around and within the bommie was consequently performed (Andrews and Mueller, 1983).