Photosynthesis and respiration in the ascidian, Didemnum molle, on the Great Barrier Reef

Photosynthesis and respiration of ascidian/algal symbiosis (Didemnum molle/Prochloron) was measured at 5 m over 24 h using an in situ respirometer at Heron Island. Several colonies were incubated within each of 3 chambers.Readings from a light sensor and oxygen probes were automatically logged and read to tape [no longer available] then averaged by computer. The rate of photosynthesis to respiration, and percent contribution of Prochloron to ascidian respiration (CPAR) was calculated. Due to cloud conditions at the time of incubations, irradience was also calculated as for idealised light conditions. Chlorophyll a content, wet and dry weights of colonies were calculated.Respiration rate was determined by Winkler titration using water samples taken from whole colonies of various sizes (g wet weight) incubated at Lizard Island (Great Barrier Reef) at 2m depth. Colonies were differentiated between white and brown.
To determine the energy contribution of Prochloron to Didemnum molle from photosynthesis and respiration rates.