CORAL STUDY EST THE SOUTHERN OCEAN — SQUIRES 



453 



The answer lies in the postulate that the physical and biological 

 characteristics of the Southern Ocean which have been outlined above 

 should provide us with an area in which to study the effects of en- 

 vironmental factors upon corals, distribution mechanisms, and the 

 changes which occur in the organisms as they move broadly throughout 

 a tremendous area such as the Southern Ocean. In short, how do the 

 corals react to their environment and how does the environment (and 

 time) modify the corals? 



Corals distribute themselves about the sea floor during a portion 

 of their life cycle in which the developing larval form is free. In 

 tropical corals the free portion of the larval life may last from several 

 days to several weeks, but this period is apparently much shorter in 

 the cold-water corals. One observed instance of the production of 

 planulae in a subantarctic coral showed that the larvae were highly 

 developed and ready for a sessile life almost at "birth." Some caution 

 must be placed between this observation and a conclusion, for it is 

 known that when tropical corals produce larvae over a span of time, 

 those first produced are less well developed than those which come later. 



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Figure 3. — Map of the currents of the Southern Ocean. (After G. A. Knox, 1960, Proc. 

 Roy. Soc, Ser. B, vol. 152.) 

 720-018—64 31 



