The substantial physiographic differences between a high island 

 system such as Kaneohe Bay and an oceanic reef like Enewetak are ref- 

 lected in the different levels of organic and inorganic supply to 

 which their respective biota must adapt. High island reefs must with- 

 stand heavy nutrient and organic loading from terrigenous runoff; by 

 contrast, external supply to atolls is minimal. Despite such opposi- 

 tion of material supply regimes, reef structure in the two environ- 

 ments is surprisingly similar. To be sure, systematic and morpholo- 

 gical differences in coral reef communities are prevalent, but both 

 oceanic margins are metabolically and structurally alike, as are the 

 lagoon patch reefs. It would appear that the major metabolic differ- 

 ences between high island and oceanic reef systems are confined to 

 interreef and possibly planktonic compartments. Reliable estimates 

 of RQ and PQ values for Kaneohe Bay sediment communities are not 

 available, so direct comparisons of Enewetak and Kaneohe Bay carbon 

 metabolism cannot be made. However, the near-zero net balance of 

 aerobic metabolism of Enewetak sediments (Fig. 1) contrasts with a 

 daily oxygen deficit at the Kaneohe Bay floor of roughly 9 mmoles m -2 . 

 The increased heterotrophy of the Kaneohe sediment community reflects 

 the abundance of systemic material supply. 



Despite metabolic and visual dissimilarities, the lagoon floors of 

 Enewetak and Kaneohe Bay are functionally and biologically comparable. 

 Such correspondence between major components of disparate reef systems 

 supports the validity of general models of coral reef ecosystems. 



LITERATURE CITED 



Emery, K. 0., J. J. Tracey , Jr., and H. S. Ladd. 1954. Geology of 



Bikini and nearby atolls: part 1, geology. U. S. Geol. Survey 



Prof. Paper 260- A. 

 Harrison, J. T. 1981. The influence of Alpheus mackayi on ecosystem 



dynamics in Kaneohe Bay. Ph.D. Thesis. Univ. Hawaii, 



Honolulu. 

 Kinsey , D. W. 1979. Carbon turnover ana accumulation by coral reefs. 



Ph.D. Thesis. Univ. Hawaii, Honolulu. 

 Marsh, J. A., and S. V. Smith. 1978. Productivity measurements of 



coral reefs in flowing water, p. 361-377. In: D. R. Stoddart and 



R. E. Johannes (eds.), Coral Reefs: Research Methods. Monogr. 



Oceanogr. Methodol. 5, UNESCO. 

 Smith, S. V. , and J. T. Harrison. 1977. Calcium carbonate produc- 

 tion of the Mare Incognitum , the upper windward reef slope, at 



Enewetak Atoll. Science 197: 556-559. 

 Smith, S. V., and D. W. Kinsey. 1978. Calcification and organic 



carbon metabolism as indicated by carbon dioxide, p. 469-484. In: 



D. R. Stoddart and R. E. Johannes (eds.), Coral Reefs: Research - 



Methods. Monogr. Oceanogr. Methodol. 5, UNESCO. 

 Smith, S. V. , and J. A. Marsh. 1973. Organic carbon production and 



consumption on the windward reef flat of Enewetak Atoll. Limnol. 



Oceanogr. 18: 953-961. 

 Sournia, A. 1976. Primary production of sands in the lagoon of an 



atoll and the role of f oraminif eran symbionts. Mar. Biol. 37: 



29-32. 



149 



