1096 THE BELL SYSTEM TECHNICAL JOURNAL, SEPTEMBER 1957 



About three and a half years ago, the Laboratories initiated a program 

 to determine the resistance to marine biological attack of materials which 

 might find application in submarine cable. The program has two primary 

 objectives: (1) acciuisition of fundamental information regarding the 

 biological resistance of a wide range of selected organic materials, and 

 (2) accumulation of immediately applicable engineering information 

 on materials. 



II. OUTLINE OF PROGRAM 



It seemed evident that marine borers or microorganisms, particularly 

 bacteria, might be expected to be the major agents of deterioi-ation. 



Marine borers are mollusks or crustaceans which bore into a material 

 for food or shelter depending on the particular organism involved. Of the 

 crustaceans, the gribble, Limnoria, is the most outstanding. Cellulose 

 material such as wood and cordage form its food supply and natural 

 habitat. There are a few references which suggest that members of the 

 genus Limnoria have bored into gutta percha. One by Chilton' refers to 

 the activity of Limnoria in the splice of a submarine cable in about 60 

 fathoms off New Zealand. Preece- identifies Limnoria as the organism 

 responsible for failure of the Holyhead-Dublin cable in 1875. Jona^ states 

 that he frequently found Limnoria in cables in the Adriatic Sea. Menzies* 

 points out that no American species is known to occur in depths exceed- 

 ing 50 feet; however, one species is known to occur off Japan at a depth 

 of 163 fathoms. He suggests that the absence of wood probably limits 

 the distribution of the animals in deep water. 



In the bibliography by Clapp and Kenk,^ there are ten, separate cita- 

 tions to the attack of submarine cables by molluscan borers belonging 

 to the family Teredinidae. In most cases, attack was confined to cellulose 

 constituents such as jute and hemp, although in a few instances mention 

 is made of attack on gutta percha insulation. Although the teredine 

 borers, along with Limnoria, are considered to be relatively shallow 

 water organisms, Roch,^ in his paper on Mediterranean teredos, refers 

 to Teredo utricnlus being obtained from depths as great as 3500 meters. 

 There is one reference^ to teredo attack of lead-co\'ered submarine cal)le. 



The other important family of boring mollusks is the Pholadidac. 

 Members of this family are sometimes referred to as the "burrowing 

 clams" and include rock, shell and wood borers. Some genera, such as 

 Xylophaga, are found in water up to 1 ,000 fathoms or more deep.'' 

 Bartsch and Rehder*^ report the penetration of the lead sheath of a sulv 

 marine cable by one of the Martesia, another genus of the family Pholidi- 



