214 THE OCEAN 



of the sea- water salts and of the materials in 

 suspension in sea- water and lying on the floor 

 of the ocean, the intensity of these changes 

 varying with the temperature and other con- 

 ditions. In nearly all deep-sea deposits 

 traces of albuminoid organic matters can be 

 detected, and the deep-sea animals on the sea- 

 fioor live by eating the superficial layers of the 

 deposits, finding sufficient organic material 

 therein to support life. The decomposition 

 of organic matter in the deposits is associated 

 with the formation of glauconite and of phos- 

 phatic grains and nodules, and other like re- 

 formations, such as reduction of oxides in blue 

 mud. 



Calcium Carbonate. — Calcium carbonate is 

 present in sea- water in the forms of the normal 

 carbonate and of the bicarbonate. The normal 

 carbonate is very slightly soluble, average 

 sea- water containing only 12 part per thou- 

 sand. Under certain conditions, however, the 

 quantity may be much increased. Thus 

 sea-water saturated with calcium carbonate, 

 that is containing the normal amount which 

 it will dissolve at a given temperature, may, 

 after remaining for a certain period in 

 contact with the same substance in a state 

 of exceedingly fine division, take up as much 

 as 0-65 part per thousand. The solution is 

 then said to be super-saturated, and after 



