Phosphorus compounds used in products other than fertilizers, such as foods, synthetic detergents, 

 and fire extinguisher compounds, can be replaced by other materials at a sacrifice of quality or at 

 increased cost. 



Potential from marine sources. The solubility of phosphate in sea water increases with decreasing pH 

 and temperature.^^ For this reason it is concentrated in deep cold waters. Phosphorite nodules are 

 formed in areas of upwelling water where the cold waters from depth, containing relatively high 

 concentrations of phosphate (as well as a high concentration of nutrients) are brought near the surface, 

 thus increasing their pH and temperature and causing phosphate to precipitate either inorganically or 

 biochemically in the form of apatite.^ ^ The areas of upwelling are generally characterized by desert 

 areas of low rainfall on adjacent lands and by the absence of large rivers, factors that result in a relatively 

 small amount of detrital sediment in the ocean. ^'' This condition favors the development of phosphorite 

 nodules. 



Offshore banks that provide topographic isolation from detrital sediments are especially favorable 

 places to look for phosphorite nodules if they are also in areas of upwelling. Figure 1 shows the known 



Figure 1. Distribution of phosphorite off 

 southern California. Source: K.O. Emery, 

 The Sea off Southern California: A Modem 

 Habitat of Petroleum (New York: John 

 Wiley & Sons, Inc., 1960). 



and probable distribution of phosphorite off southern CaUfornia. Note the association with topographic 

 highs. Figure 2 shows the worldwide distribution of upwelling water, phosphate deposits, and related 

 phenomena. As the map indicates, the areas of upwelling and areas of known phosphorite nodule 

 deposits are mostly along the western margins of continents. The largest nodule deposit off the coast of 

 the United States is off southern California where Emery^^ has estimated over one billion tons. 

 According to Mero,^* not more than 100 million tons of this deposit is economic grade. Most of it is in 

 water less than 1,800 feet deep. These figures include only nodules lying on the surface. The nodules 

 contain up to a maximum of 29 per cent PaOs compared with land-based phosphate ore that generally 



H. U. Svendiup et al, "Reseaich Within Physical Oceanography and Submarine Geology at the Scripps Institution 

 of Oceanography During April 1945 to April 19^6," American Geophysical Union Transactions, Vol. 27, No. 4, pp. 

 571-573, August 1946. 



2 3 



V. E. McKelvey and Livingston Chase, "Selecting Areas Favorable for Subsea Prospecting," in Exploiting the 

 Ocean (Washington, D.C.: Marine Technology Society, 1966). 



24 



K. O. Emery, "Geological Methods for Locating Mineral Deposits on the Ocean Floor," in Exploiting the Ocean 

 (Washington, D.C.: Marine Technology Society, 1966), p. 32. 



K. O. Emery, The Sea off Southern California: A Modem Habitat of Petroleum (New York: John Wiley & Sons, 

 Inc., 1960). 



^* John L. Mero, The Mineral Resources of the Sea (New York: Elsevier, 1965). 



VII-144 



