ABSTRACT: Carbon and oxygen isotopic ratios, measured along the growth axis of branches from colonies of the scleractinian coral Acropora formosa collected at 2 and 12 m depth at Yonge Reef (Northern Great Barrier Reef, Australia), were compared to metabolic rates. Measurements of primary production, respiration, temperature and irradiance were carried out in situ twice, in winter and in summer, and skeletal isotopic analyses were performed at 2 reference points corresponding to metabolic measurements. There was no evidence of any relationship between oxygen isotopic ratio and productivity. Skeletal delta¹³C values and the rates of productivity showed a statistically significant positive relationship as predicted by the model proposed by Goreau (1977a: Proc 3rd Int Coral Reefs Congr 1:395-401); delta¹³C increased as a function of increasing productivity. The scattering of delta¹³C observed particularly during summer demonstrates that the relationship between delta¹³C and primary productivity is not very tight and that other internal and external parameters probably operate to explain the delta¹³C variability.

KEY WORDS: Acropora formosa · Productivity · Skeletal delta¹³C and delta¹⁸O

Published in MEPS Vol. 157 (1997) on October 16
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1997