National Geographic : 1971 Aug
life-support systems to color schemes for space stations and future undersea dwellings. Other crews that came before and after ours laid the foundations for study of other crucial undersea problems. One team, work ing with four different commercial pesticides, proved that even minute doses seriously affect the respiration of coral polyps. As it is, those builders of great reefs barely keep ahead of erosion-and in fact succumb to such preda tors as the crown-of-thorns starfish*-so even minor pollution could be fatal. 288 Another team concentrated on sonic com munication among fish. Although man cannot differentiate very faint sounds under water, electronic recording devices captured a broad range of noises. Many are still unidentified, but their ultimate value to undersea farming could be immense. If we can reproduce the feeding signals of various fish, we might be able to lure large numbers into submarine pens. At the same *This killer was described by James A. Sugar in "Star fish Threaten Pacific Reefs," GEOGRAPHIC, March 1970.