DEEP-SEA ANIMALS 



The knowledge of the existence of animal life in the deep sea was first provided 

 by a broken submarine cable that was brought up for repairs from a depth of over 

 6,600 feet in the Mediterranean in 1860. Attached to this cable were bivalve 

 mollusks, gastropods, hydroids, alcyonanlans, and worms. Recently the Danish 

 Deep-Sea Expedition (1950-52) In the research ship Galathea obtained living 

 animals of several phyla. In addition to viable bacteria, from a depth of greater 

 than 33,000 feet in the Philippine Trench. The animals obtained at this great depth 

 included about 40 actlnians, 5 echiurld worms, 80 myrlotro'chus, 1 elasipod holothurlan, 

 5 bivalves, and species of amphipods and tanalds. 30 



Much of the animal life In the deep sea Is truly endemic, as shown by the 

 presence of vast numbers of species and genera found consistently In the deep zones. 

 However, many deep-sea species are eurybathic; that is, they endure great ranges 

 of depth. These animals are of great biological Interest because of their adaptability 

 to conditions of depths. Some of the more outstanding eurybathic forms which are 

 able to inhabit the ocean from shallow to great depths are: (1) pennatularlans — to 

 11, 900 feet, (2) polychaetes - to 16,500 feet, (3) bivalves - to 14,500 feet, 

 (4) snails - to 9,900 feet, (5) starfish - to 8,000 feet, and (6) sea urchins - to 

 16,000 feet. 3 



Species of marine fish are also capable of Inhabiting the environment of total 



darkness, low temperature, and high hydrostatic pressures which prevails in deep 



waters. In this area of very little or no light penetration, there is a marked increase 



in reddish and dark-colored animals. Abyssal fishes are characterized by strange 



and weird anatomical adaptations. These adaptations ore concerned with structural 



modifications fitting the animals better to survive in faintest light or In utter and 



perpetual darkness. They are mainly along three lines: (1) tactile structures, 



(2) food-procuring contrivances, and (3) light production. The following are a few 



of the deep-sea fishes that were obtained on various deep-sea expeditions: 



(1) Macropharynx longicaudatus , length 15. 1 cm, from 11,500 feet, (2) GIgantactis 



macronema, length 13.3 cm, from 8,250 feet, (3) LInophryne macrodon , length 



5. 3 cm, from 5, 000 feet, (4) Malacostus Indicus , length 8 cm, from 3, 000 to 

 8,250 feet. 3/31 



PROPOSED FIELD AND LABORATORY INVESTIGATIONS 



The ocean environment is so broad and complex with so many factors Involved, 

 such as marine life, depths, pressure, temperature, salinity, dissolved oxygen con- 

 centration, and bottom sediments, that a single test procedure cannot be expected 



11 



