The 2x6x 1/2-inch wood panels were cut from sound lumber, and the surfaces 

 were cleaned with alcohol and then covered with plastic to avoid contamination with 

 terrestrial microorganisms. The plastic covers were removed just before the test 

 specimens were submerged. The wood panels were employed to collect specimens 

 of any deep sea fungi and marine borers present on the ocean floor. 



The sections of the 3-foot-long plastic rods, tubes, and pipe, and the rubber 

 tubes were treated in different ways. One section of each specimen was roughened, 

 a second section was wrapped in burlap, a third section was wrapped with plastic 

 tape, a fourth section was wrapped with rubber electrical tape, and a fifth section 

 was left smooth. The various wrappings provided a favorable foothold for the attach- 

 ment and growth of deep sea fouling and boring organisms. To determine the relative 

 resistance of the two types of tape to biological deterioration, two small pieces of 

 wood were secured to a plastic rod by wrapping each of them with one of the two 

 types of tape. Finally, two pieces of 2 x4x 30-inch untreated fir wood were fitted 

 around both ends of each plastic specimen to act as bait to attract and lead borers 

 into direct contact with the plastic materials. 



Four different kinds of rope, such as synthetic plastic fiber rope (nylon and 

 polypropylene) and natural fiber rope (cotton and manila), were placed on the bio- 

 racks. Electrical cables covered with either rubber or plastic insulation of various 

 thicknesses were also placed on the racks. A small piece of pine wood was fitted 

 around each electrical cable specimen to act as bait for marine borers. Another 

 group of electrical conductors placed on the bio-racks consisted of a 0.015-inch- 

 thick insulation over a No. 16 tin-coated copper wire. The materials used In the 

 formulation of the insulation are presented in Table 3. The wire specimens were 

 15 inches long; some were stressed (coiled) and some were nonstressed (straight). 

 Stress was applied by coiling a 15-inch specimen lightly around a 1/4-inch-diameter 

 glass rod and then removing the rod. Both ends of each specimen were sealed with 

 two coats of silicone rubber cement. The various test specimens were positioned so 

 that one set of ropes and electrical cables would be buried in or exposed near the 

 sediment (in which bacteria are ordinarily most active) and an identical set would 

 be exposed about 3 feet above the sediment. 



Metal test specimens were also placed on the STU, but materials containing 

 antifouling paints or other toxic substances were excluded from exposure aboard the 

 STU. The current velocity at a depth of 5,640 feet (0.033 knot) was not great 

 enough to carry away any water-soluble toxic substance which might alter the 

 natural biological fauna found in the immediate vicinity of the STU. 



