31 



animals in their respiration, but by the oxidization of th3 docaving 

 carcasses of animalc and plants, and neasur events of the actual rate 

 of impoverishment under the varyinr- conditions actually existing in 

 the sea are luuch v/anted in connection with a variety of biolo-ilc 

 problens. ''' 



If th-3re were no ncans of renewing oxygen fron above, the under- 

 lying ^vater would soon be absolutely stripped of this vital necessity, 

 as the deeps of the Black Sea actually are, instead of which we find 

 the bottom Y/aters of the basins nearly saturated v/ith oxygen, con- 

 trasting Y.'xth considerable deficiencies in the mid-strata under the 

 Tropical belt of the Atlantic, and generally in the mid-depths of the 

 Pacific. The onl:-- knovm means by which this state can be maintained, 

 is by sinking currents, or by turbulence, carrying down into the 

 deeps the water that has beco:-_:e saturated with oxygen near the sur- 

 face. We need to learn whether the mass sinkings" of ox^^gen-laden 

 water, that supply the bottoms of the basins, are as strictly con- 

 fined to the Arctic and Antarctic Seas, in their respective winters, 

 as now seeT.3 probable; also how this water comes to be distributed 

 over the bottoms of the ocean basins so uniformly that the abyss is 

 about unifornly rich in oxygen over vast areas, in spite of the ride 

 local variations in abundance of animals etc. 



The relationships that the paucity of oxygen in the equatorial 

 raid-strata of the Atlantic bears to the drifts, toward the equator, 

 of sinking water from nid- latitudes north and south, that are re- 

 vealed by^the "Lleteor's" profiles, remains to be worked out; and we 

 still await a satisfactory interpretation, in terns of circulation 

 of the poverty in oxygen of the mid- strata of the Pacific. The local 

 lactors (e.g. abundance of plants and animals, amount of doco:Toosition 

 01 organic matter taking place at different levels) responsible for 

 the very notable divergence between the quantitative distribution of 

 oxygen and tnat of salinity, as revealed by the most recent meridion- 

 al profiles of the oc:ans, also offer an interesting problem; like- 

 wise the relative importance, from the standpoint of oxygen intake, 

 01 coastlines of different characters, with their different types of 

 wave action and of turbulence. How effective a source of oxygen 

 supply for the surrounding neighborhood is, for instance, a rockv 

 headland upon which the surf beats constantly? We have yet to leern 

 how deep simple turbulence is able to maintain the oxygen supply close 

 to tne saouration point in different regions under different con- 

 ditions. How are we to interpret, in this respect, the very rapid 

 falling off of oxygen, with depth, in the upwelling waters off 

 Call form a; and is this falling off characteristic of the other rerions 

 where upwelling takes place on a broad scale? 



Finally, the problems of the oscillatory (pure wave) currents 

 01 tne sea deserve a word. Two classes of phenomena come in question 

 xiere,_one the ordinary storm waves, when not complicated by tidal 

 cnurnings, tne other the internal boundary waves' or vertical undula- 

 tions at sore mid-level that winds and other forces are known to set 

 in motion and that have been observed, on occasione when no a-Dparent 

 cause could be ascribed to them. .^i^^ -cno 



Although the importance of learning the depth of storn-wave 

 case, and the efficacy of storm-wave oscillation down to that level 

 as a transporter of heavy materials, is obvious from the geologic 



