152 THE OCEAN FLOOR 



late Prince Albert I of Monaco obtained northwest of 

 Madeira from a depth exceeding 6,000 meters a 

 bottom-living abyssal fish, Grimaldichtys projundis- 

 simus. Nearly half a century later, in 1948, O. Nybelin 

 of the Swedish Deep-Sea Expedition with the "Alba- 

 tross" obtained bottom-living organisms from a depth 

 exceeding 7,600 meters.^ 



However, there is no doubt that with increasing 

 depth there is a decrease in the density of population 

 on the ocean floor, and the question of whether the 

 very deepest layers of the ocean are azoic or are not 

 remained open. Laboratory experiments by Fontaine 

 seemed to indicate that pressures exceeding 700 

 atmospheres, equivalent to 7,000 meters of water, 

 have destructive effects on the protoplasm of living 

 cells.- 



Life in very great depths must be highly precarious. 

 No trace of daylight can penetrate even the clearest 

 sea water below a depth of approximately 3,000 feet. 

 The progressive loss of light is due to an absorption by 

 the water itself and to light scattering against suspended 

 particles, water molecules, and salt ions. Such rapid 

 attenuation of light naturally limits plant life to a 

 relatively thin, euphotic, surface layer, where enough 

 radiant energy to support photosynthesis is present. 

 This total lack of abyssal plant life must have serious 

 consequences for the maintenance of animal life, which 

 in great depths apparently can subsist only on crumbs 

 falHng from the sunlit table near the surface. 



