The Variety of Substrata 65 



ecology of fouling is necessary for success in the very practical prob- 

 lem of preventing this attachment. In experiments with different 

 types of materials with which to coat submerged objects including 

 ship bottoms, it was found that no surface could be devised which 

 was so smooth, so slippery, or so soft that a barnacle cyprid could not 

 gain a foothold. Tests showed that fouling could be prevented only 

 by covering the ship's hull with paint that emitted copper or other ions 

 strongly toxic to the attaching stages, as illustrated in Fig. 3.3 (Woods 



C. M. Weiss, Woods Hole Oceanographic Institution 



Fig. 3.3. Bottom of boat showing reactions of fouling organisms to different anti- 

 fouling paints. Fouling has been prevented on port side by emission of ions from 

 cuprous oxide paint. On the starboard side fouling organisms have attached be- 

 cause the emission from the metaUic copper paint used on that side has been in- 

 hibited by the coupling action of the galvanized iron patch seen at right of 



propeller. 



Hole Oceanographic Institution, 1950). Without an effective anti- 

 fouling paint a battleship is said to require 30 per cent more fuel to 

 maintain cruising speed within 6 months after launching, and its top 

 speed is seriously reduced. The research program on the ecological 

 relations of fouling organisms and on poisoning methods undertaken in 

 American marine laboratories during World War II was reported to 

 have saved the United States Navy 10 per cent of its entire fuel bill. 

 The substrata used by plants and animals are not restricted to in- 



