Reef crest

Fig. 2.5.7. A. Piecrust Porolithon covered) surface of the reticulate patch reefs. This is typical also of the leeward reef crest. One Tree Reef. B. Delicate and diverse coral development in 10—1 2 m of water on leeside of One Tree Reef.

Note All estimates exclude the activities of the outer slopes. However in the case of Canton and Fanning Islands, these do not contribute to the virtually closed systems. These two reefs also lack reef-flats subject to inflowing water because of the continuous islands along the reef crests. 1 = Mean water level 2 = low water springs. 

Few studies to date have adequately estimated the overall metabolic activity of an entire reef system. Table 2.5.2 summarizes the available data, but even so, the estimates extend only from crest to crest and exclude the outer slopes. The estimates for One Tree Island Reef and Lizard Island Reef are the weighted means of a series of zonal studies. The Canton estimate is based on overall long-term changes. The principa) conclusion to be gained from such data is that the reef systems reported clearly show little or no net... 

Low-crested and submerged structures (LCS) as detached breakwaters and artificial reefs are becoming very common coastal protection measures (used alone or in combination with artificial sand nourishment).As an example, a number of systems and typical applications of shore-control structures is shown in Figs. 20.4-20.7. 

Structural design aspects of low-crested structures are relatively well described in a number of publications.Some useful information on the design of breakwaters on reefs in shallow water can be found in Jensen et al. ... 

Moreover, the force coefficients Cd, Cl, and Cm are also given as a function of the Reynolds number for different locations and boundary conditions which may represent different practical applications (scour protection on the sea bed, artificial reef, slope containers, and crest container of a surface piercing structure such as revetments, seawalls, groins, etc.). The proposed values of Cd, Cm, and Cl have been determined on the basis of systematic laboratory experiments. ... 

LCBs mimic in some manner the functioning of coral reefs, that however have usually a much wider crest and a narrower range of submergence/emergence due to their generation mechanism. As a consequence they are sometimes named also reefs. ... 

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