142 THE OCEAN FLOOR 



or less than 9,000 feet from the surface. This difference 

 in level of 16,000 feet over a distance of 10 nautical 

 miles corresponds to a grade of 25: 100. 



Here we are quite close to the breakthrough in the 

 ridge, the famous Romanche Channel, which has never 

 been located by soundings but which, according to 

 temperature measurements, opens a passage for the 

 nearly ice-cold Antarctic water from the southwest 

 into the secluded basins of the eastern Atlantic Valley. 

 This channel is assumed to be about 15,000 feet deep, 

 leaving undisturbed the still lower water layers of the 

 Romanche Deep below the threshold level. 



Investigating the contents of the water bottles 

 lowered to the bottom of the Romanche Deep. Koczy 

 found that the distribution of certain elements char- 

 acteristic of the ocean water was as shown in Figure 46. 

 Although there is no noticeable break in the curves for 

 salinity and temperature, there are very pronounced 

 and abrupt changes in the contents of silica, phosphates, 

 and optical particles ("turbidity"), occurring at about 

 20 meters or, say, 65 feet, above the bottom. From these 

 breaks, corresponding to the maxima in the three 

 curves, there is a gradual decline to the much lower 

 figures found in the deepest water sample, taken only 

 25 feet from the ocean floor. 



How this strange stratification shall be interpreted is 

 largely a matter of conjecture. It should be pointed 

 out, however, that an analogous trend of the curves 

 was observed in other localities, where the depth was 



