Fig. 4. Intensity of assimilation (A, ,ig 

 C/g 'day) of food labeled with C-'-^ by coral 

 with various food concentrations (K, ug 

 C/liter); 1, Dissolved organic matter 

 (algae protein hydrolysate) ; 2, Bacterial 

 plankton; D, assimilated food, % of 

 expenditure for metabolism (with correction 

 for loss of C-'-^ during time of experiment); 

 Ki and K2--probable natural concentrations 

 of bacteria and dissolved organic matter in 

 the water around the coral reefs. 



/^/^ zoo 300 ¥00 m/c 



coral come in contact, the polyps of the more aggressive ("stronger") sptvies 

 extend their mesenterial filaments toward the "weaker" species, enclose and 

 digest its polyps. Nbst aggressive are the massive, slowly growing species of 

 Favia , "weakest" are the species of Agaricia , which live at considerable depth 

 and, apparently, do not experience great competition from the other 

 madreporaria. Acropora occupy an intermediate position. 



The growth rate of hermatypic corals depends to a great extent on the 

 level of illumination at the point of attachment of the colony. In the dark, 

 the hermatypic corals die within a few months. Under optimal growth 

 conditions, in two or three years, coral colonies can grow to a diameter of 

 10-20 cm, doubling their size each year. The mean age of colonies in the 

 zones of active growth (FL, Br, But) is about 5 years, the maximum age--up to 

 140 years. The mortality of young colonies is great--20-40% within 3 years 

 (Connell, 1973). In spite of the high rate of growth of young corals, 

 replacement of their populations after passage of a destructive typhoon is 

 quite slow. The additional stage of settlement of the damaged frontal zone 

 with corals and the succession of communities which follows extend over a 

 period of 3-5 years (Stoddart, 1962, 1974; Glynn, 1973), while full 

 restoration requires over 30 years. 



The composition and populatio 

 such natural enemies as the boring 

 (Pang, 1973). They drill holes in 

 resistance to the surf. Many reef 

 polychaeta, gastropoda, fish) feed 

 their outer layer. The most dange 

 Acanthaster planci . Over the last 

 animal on certain reefs in the Ind 

 observed (Endean, 1973; Connell, 1 

 stars are usually found quite rare 

 km"^. Following massive breeding, 

 several individuals per 10 m^. Mo 

 destroy up to 90% of the corals, 

 after they pass. 



n of corals i 

 sponges Clio 



to the living 



animals (sea 



on the coral 



rous predator 



10-15 years, 



ian and Weste 



973). These 



ly on the ree 



their populat 



ving over the 



The coral req 



s significantly influenced by 

 ne and the mollusks Ithophaga 

 coral and decrease its 

 urchins, sea stars, crabs, 

 , eating the polyps or removing 

 for the coral is the starfish 

 population explosions of this 

 rn Pacific Oceans have been 

 large--mean diameter 30 cm-- 

 fs, a few individuals per 

 ion density increases to 

 reef in compact groups, they 

 uires many years to recover 



176 



