Primary production, respiration and bathymetric distribution were investigated in the 10 most common zooxanthellate soft corals on mid-shelf reefs of the Great Barrier Reef (Davies and nearby reefs). Oxygen flux of corals collected from 5-20 m was measured at 6m depth over 24 hours using data-logger respirometers.
The photosynthetic and respiratory rates of 10 zooxanthellate and 2 azooxanthellate soft coral genera were determined. Colonies were collected from depths of 5, 10 and 20 m and measured at 6 m depth - only colonies which appeared to have recovered from handling were used in respirometric measurements.
Irradiance and oxygen flux rates of the 10 zooxanthellate taxa were measured. The degree of contraction or expansion of each soft coral was recorded every 3 hours during the day and once or twice at night for every 24 h respirometry run.
Transects (25 m x 0.5m, perpendicular to the slope) were surveyed at 5 m depth intervals from 5-30 m on windward, leeward, northern and southern flanks (note not all went to 30 m deep); mean density of all common soft coral taxa were recorded, and photosynthetically active radiation (PAR) was measured.
