Turnover of photosynthetically fixed carbon in reef corals

Siderastrea siderea and Montastrea annularis were labeled in situ with NaH¹⁴CO₃. The corals were sampled over a period of 11 days and the radioactivity remaining in the ethanolsoluble and ammonia-soluble fractions measured. Total radioactivity in the corals fell to about 1/3 after one night and then to about 1/3 in the next 10 days. The ethanol-soluble radioactivity is probably converted to the less soluble, ammonia-extractable, material in the dark.Contribution No. 1514 from the University of Miami, Rosenstiel School of Marine and Atmospheric Science, 10 Rickenbacker Causeway, Miami, Florida 33149, USA.