SEPT. 1] THE INFLUENCE OF ORGANISMS ON THE COMPOSITION OF SEA-WATER 



35 



be recognized by their composition (see Table IV). In the deep water masses 

 of the Atlantic, characteristic mean values for preformed phosphorus may be 

 assigned which differentiate the North Atlantic dee}) water, the circumpolar 

 water, and the Antarctic deep water. The dispersion of measurements for 

 samples from each of these water masses is not greater than that of the measure- 

 ment of inorganic phosphorus. 



Table IV 



Preformed Phosphorus Content (P p ) of Deep Water Masses of Atlantic Ocean 



(mg atoms m 3 ) 



Water mass 



Criteria 



No. 



Dispersion (a) 



samples mean Individual Analytical 

 estimate method 



North Atlantic 

 deep water 

 59°N-34°S 



Circumpolar 



water 



24°S-69°S 



Antarctic 

 deep water 



49°S-69°S 



S 34.85-35.0% 

 T 2-4°C 



S< 34.75 % 

 T 0-1.99°C 



S< 34.75%, 

 T<0°C 



102 0.74 ±0.13 +0.12 



41 1.50 ±0.19 +0.23 



26 1.G7 ±0.13 +0.23 



c. Regeneration of nutrients 



It has been implicit in the foregoing discussion that the oxidation of organic 

 matter has gone to completion in the deep water. This is not absolutely correct 

 since the deep sea is inhabited by organisms and various organic residues may 

 be detected in its waters. Intermediate products of decomposition may occur 

 in significant quantities in places where organic matter is decaying in quantity, 

 and their distribution in the sea provides useful information on the regenerative 

 part of the biochemical cycle. Although a variety of organic materials may be 

 detected in sea-water (Duursma, 1960), discussion will be limited to the few 

 which have been sufficiently studied to provide insight into the regeneration of 

 phosphate and the nitrogenous nutrients. 



The phosphorus of organisms is present for the most part in organic com- 

 bination, forming molecules many of which are known to be of great physio- 

 logical importance. On decomposition such molecules are liberated into the 

 water as dissolved substances. On the oxidation of these materials, presumably 

 by bacterial action, the phosphorus is released as phosphate in the ionic form. 

 The method traditionally employed on shipboard measures only the phosphorus 

 which has been completely regenerated, i.e. that present as inorganic phosphate 

 ions. Treatment of a sample with strong oxidizing agents decomposes the 



