were also found attached to the rope (Figure 13). The recovered polypropylene and 
nylon ropes were examined for signs of lacerations or cuts by fish, but no evidence 
of such an attack was found. The seriousness of fish bites on plastic ropes exposed in 
the Atlantic Ocean has been reported, !2,13 Slight amounts of hydroid growth were 
found on the STU frame, which was coated with a white vinyl paint. Typical fouling 
growth such as barnacles, bryozoa, and other attachment organisms were not found on 
the painted surface. 
Marine Growth on STU Materials 
Metal Specimens. The majority of test specimens on the STU were metals and 
metal alloys to study the effects of the deep-ocean environment on corrosion, 
The major fouling organisms found attached to the surface of metal specimens 
were species of hydroids belonging to the phylum Coelentra (the polyps). Trace to 
heavy hydroid growth were found on all the metal test specimens (Figure 14). Some 
of the hydroids were 3 to 4 inches long. The heaviest growth occurred on the surface 
of a 1 x 6 x 3/16-inch No. 316 stainless steel test specimen. Trace to very light 
growth occurred on the surface of copper based alloys and manganese bronze test 
specimens. The surface of the metal specimens where the hydroids were attached 
was not affected, This area was examined under a microscope for signs of corrosion 
in the form of pits. 
When a 2 x 2 x 1/8-inch stainless steel coupon used as a spacer between a 
test-specimen holder and a wood panel was pried loose from a wood surface, there 
were four elongated pits on the surface of the coupon. The pits contained black 
corrosion products. Several marine borers had penetrated the wood and were in 
direct contact with the metal, but no pitting of the metal surface was evident; how- 
ever, there were red rust stains at these sites. 
Two different kinds of surpulid worm tubes constructed of different materials 
were found on the test panels. One of these tubes was made of white calcareous 
material which was hard and brittle. Several such tubes were found attached to the 
surface of stainless steel panels which were partly exposed in the sediment (Figure 15). 
Approximately 1/2 inch of one end of a 1-inch worm tube was extended outward at 
right angle to the panel. This particular form of tube construction made by a surpulid 
worm was also found on coated and painted test panels, and on plastic materials 
(Figure 16). 
The second type of worm tubes was composed of fine and coarse sands, Forami- 
nifera tests, glauconite, and debris cemented together. A tube approximately 4 inches 
long was found on the surface of a Hastelloy C metal panel which was partly buried in 
the sediment (Figure 17). After the panel was cleaned in an acid bath (18 percent HCI 
by volume), the impression of the worm tube was still clearly visible on the metal 
surface (Figure 18). 
