as carbonates and bicarbonates; the content of free CO2 and HoCOo decreases wlih 

 increasing temperature and salinity. In general, the carbon-dioxide content is 

 higher in the deeper waters than at the surface layers. 



Hydrogen-Ion Concentration 



Sea water is normally alkaline in reaction, v/ith a pH range of 8.0 to 8.4 in 

 surface v/aters. In stagnant basins where large amounts of H2S are present (anaerobic 

 condition), the pH may approach 7.0. 



MARINE ORGANISMS RESPONSIBLE FOR MATERIALS DAMAGE 



The results of the literature survey on the biological deterioration of various 

 engineering materials in the marine environment are tabulated in the Appendix. 

 Materials attacked by biological organisms, the type of damage resulting from attack, 

 the geographical location where the damage occurred, biological organisms respon- 

 sible for the damage, and other pertinent information to the subject are listed and 

 referenced. The following discussion is based on that data. 



Crustaceans 



Crustaceans responsible for extensive damage to materials in the sea include 

 species of Limnoria also known as gribbles. Limnoria are related to the shrimps and 

 lobsters and are world-wide in distribution. They are normally found attacking the 

 surface of submerged wooden structures in shallow waters (harbors). However, 

 materials other than wood, such as the gutta-percha coverings of submarine cables 

 at a depth of about 360 feet in the ocean, have been penetrated by Limnoria lignorum . 

 One species of Limnoria off the coast of Japan is known to Inhabit depths of approxi- 

 mately 1,000 feet. It is suggested 5 that the absence of suitable edible materials 

 in the deep-ocean environment may be one of the limiting factors which confine 

 Limnoria to shallow water. 



Species of Sphaeroma, also a crustacean, are found burrowing into sandstone 

 in San Francisco Bay and into sea walls made of clay stone in Hawk Bay, New Zealand. 

 Sphaeroma are less important economically than Limnoria in the amount of damage 

 they cause to engineering materials. 



Mo Husks 



The mollusks responsible for extensive damage to various types of engineering 

 materials in the sea include species of Teredo , Bankia , Xylophaga , and Martesla . 

 These mollusks are related to the clams and the oysters and are world-wide in distribution. 



