Chapter 9 



Reef Processes: Energi; and Materials Flux 



JAMES A. MARSH. JR. 



Marine Laboratory/, Uniuers/ty of Guam 

 Mangilao, Guam 96923 



INTRODUCTION 



A number of significant studies of reef community 

 processes have been conducted at Enewetak. These stud- 

 ies have made major contributions to an understanding of 

 that particular system. Their significance also lies in the 

 development of methodology and of a general approach to 

 understanding whole ecosystems. Such studies have 

 strongly influenced the context in which many ecologists 

 think about reef systems and have probably had a broader 

 influence on ecology generally. 



One of the earliest and most important studies, con- 

 ducted during the first year of Enewetak Marine Biology 

 Laboratory (EMBL) operations, was that of Odum and 

 Odum (1955). This was a remarkable attempt to look at 

 the reef ecosystem as a whole and to relate structure to 

 function. It has been widely cited not only by reef 

 researchers but also by other ecologists and has had an 

 impact on ecology generally. It generated great interest 

 both for its approach and for its specific findings and con- 

 clusions. The Odums did an impressive amount of work 

 during their 6 weeks at the field site and then used this as 

 the basis for far-reaching extrapolations. Additionally, they 

 stimulated a great deal of interest in reefs as ecosystems 

 and prompted many other researchers to undertake further 

 studies, apparently if only to prove the Odums wrong in 

 some cases. Their seminal study thus occupies a central 

 position in a chapter on ecosystem processes of Enewetak. 



A more recent study utilizing the same approach was 

 conducted by the SYMBIOS team in 1971 (Johannes et 

 al., 1972). The team, consisting of some 25 scientists with 

 a variety of diverse but related interests, spent 2 months 

 studying transects near the earlier Odum transect. This 

 much larger scale effort confirmed and extended many of 

 the original findings of the Odums in a repeat demonstra- 

 tion of the utility of the upstream-downstream sampling 

 methodology and particular processes and phenomena. 



In addition to community metabolism, other important 

 studies to be discussed in this chapter have focused on cal- 

 cification processes at the ecosystem and organismal level, 

 on nitrogen and phosphorus cycling, on the role of detritus 

 (coral mucus and algal fragments), on coral nutrition, and 

 on ecological relationships of reef fishes. Noteworthy 

 research gaps include the lack of attention directed to eco- 

 logical relationships involving humans and the apparent 

 dearth of information on the impact of atomic testing, even 

 though EMBL and the operations it evolved into have been 

 supported by the Atomic Energy Commission and its suc- 

 cessor organizations. 



Several other papers resulting from work at Enewetak 

 are often cited and have had a major influence on the 

 thinking of reef scientists. These include papers by Goreau 

 (1959), Hiatt and Strasburg (1960), and Muscatine (1967). 

 Other papers of general interest are those by Knutson et 

 al. (1972), Smith (1973), and Hobson and Chess (1978). 



It is noteworthy that the work supported at EMBL and 

 its successors includes few general descriptive studies. 

 There are perhaps two reasons for this. First, much of the 

 descriptive information that is available was accumulated 

 incidentally during the course of other types of studies. 

 Second, and perhaps more important, much information 

 was previously available as a result of extensive surveys 

 (some of them quantitative) during Operation Crossroads. 

 Hence, much of the descriptive background for more func- 

 tional studies was already available when EMBL began 

 operations. Nevertheless, additional descriptive informa- 

 tion, with an emphasis on quantitative observations, would 

 probably be helpful. 



The large number of geological, physical, and geochem- 

 ical studies carried out at Enewetak makes this one of the 

 most thoroughly studied reef systems in the world. It is 

 ironic that much of this information is still apparently scat- 

 tered in various sources, especially unpublished ones, and 

 perhaps available only in the files of different funding agen- 

 cies. A careful synthesis of such potentially available infor- 

 mation might lead to a more comprehensive overview of 

 the Enewetak ecosystem than is otherwise possible — an 

 overview based on more than an "expedition" mentality. It 

 is thus unfortunate that the ecosystem with the greatest 



159 



