ON CHANGES IN THE SEA AND THEIR RELATION TO 



ORGANISMS. 



By J. F. McClendon. 



PART I. 

 INTRODUCTION. 



The sea and air form the circulating media for the living organisms of 

 the world, and although the air circulates so rapidly that no correlation 

 between local faunas and floras and local composition of the air has 

 been found, the local composition of the sea is distinctly affected by 

 living organisms. The local changes in the composition of the sea are 

 the subject of the present paper. These changes are due chiefly to 

 organisms, but partly to meteorological causes. The circulation of 

 the air certainly affects the sea, but the circulation is so rapid that my 

 attempts at correlating meteorological observations (made for this 

 purpose) with changes in the sea have not been encouraging. 



The water evaporated is returned with addition of fixed nitrogen 

 from electric discharges or falls on the land and is returned with various 

 salts, chiefly CaCOs, and with fixed nitrogen and other products of 

 organisms. Various seaweeds absorb CO2, thus leaving an excess of 

 CaCOs, which has a very low solubility and is constantly being precipi- 

 tated in certain warm seas and is precipitated within the bodies of 

 organisms in the surface waters of all seas. In working out the relation 

 of H-ion concentration (pH) to the solubility of CaCOa in sea-water, I 

 found that all sea-water is supersaturated with CaCOs, and wdll lose 

 some of it if shaken with calcite or aragonite crystals. 



The study of the local changes in the sea is complicated by the pres- 

 ence of currents. The surface currents are due to winds, but, owing to 

 the inertia of the water, they do not change as rapidly as the ^\^nd and 

 hence are indicators of the prevailing winds (fig. 1), except where they 

 are deflected by bodies of land or rotation of the earth. The largest 

 currents may be constant (fig. 2), but the smaller currents show seasonal 

 variations. Very few constant or seasonal vertical currents have been 

 mapped, but vertical currents must be universal. McEwen has col- 

 lected an enormous mass of evidence to show the presence of vertical 



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