ASSIMILATION OF PHOTOSYNTHETIC PRODUCTS OF ZOOXANTHELLAE BY A REEF CORAL.

1. The hermatypic coral, Pocillopora damicornis was incubated in the laboratory and in its reef habitat with Na214CO3 for 1-24 hours. Controls were incubated in darkness. 14C fixation in light exceeded that in darkness. 2. Fractionation of corals labeled on the reef for 24 hours revealed that 35-50% of the total 14C fixed appeared in the animal tissue lipid (as 14C-glycerol) and protein. From a comparison with dark controls it is concluded that photosynthetic products of zooxanthellae are translocated to host coral tissue. The skeletal organic matrix also acquires 14C. 3. Zooxanthehellae isolated from corals and incubated in a homogenate of host coral tissue selectively release glycerol and traces of other organic material including glucose, alanine, and glycolic acid confirming previous observations.