Corals were collected by scuba along 2 transects at Davies Reef in October 1980, and February, July and December 1981. Transect A-B ran from 1-17 m deep on the seaward margin of the reef flat. Transect C-D ran from 1-51 m deep on the seaward reef slope. Collection date, sea surface temperature, transect, depth and coral species were recorded.
For the experiments, either a group of four 12 cm terminal branches of Acropora formosa or Acropora valenciennesi, or one 9 cm diameter colony of all other species were placed in a chamber and changes in dissolved oxygen content measured. Light measurements of photosynthetic photon flux density were in units of microEinsteins (400-700 nm) per square metre per second. Corals were incubated in the dark and light for periods of 20-30 min, arranged in order of increasing light intensity.
The corals were frozen at the end of the experiment; chlorophylls and accessory pigments were extracted with 3 volumes of 20% tetrahydrofuran in methanol (v:v), separated and quantified by high performance liquid chromatography. Ten replicate coral samples were analysed for protein content.
