INCORPORATION OF STRONTIUM (90SR2+) INTO THE SKELETON OF THE HERMATYPIC CORAL GALAXEA-FASCICULARIS

The rate of Sr-90(2+) deposition in Galaxea fascicularis was linear with respect to Sr2+ concentration (0.01-20 mM) and refractory to DCMU (1-mu-M), an inhibitor of photosynthesis. The deposition rate of Sr-90(2+) in polyps incubated under a light intensity of 200-mu-E.m-2.s-2 was not significantly different from that in polyps incubated in total darkness. The deposition rate of Ca-45(2+) (1-20 mM), on the other hand, exhibited saturation kinetics. In addition, it was DCMU sensitive and enhanced by light. Our results therefore support observations reported elsewhere that K(Sr)A is inversely correlated with growth rate in reef corals. However, Sr2+ and Ca2+ deposition in G. fascicularis does not appear to involve similar biochemical mechanisms.