6 Marine Microbiology 



CHEMICAL COMPOSITION OF SEA WATER 



Ten major components (Table 2) constitute more than 99 

 per cent of the salts in solution in sea water. The remainder is 

 made up of a large number of other elements, some in concentra- 

 tions of less than 1 X 10~^" mg/liter. Many of the minor constit- 

 uents are concentrated several hundredfold or thousandfold in 

 certain marine plants or animals; thus their concentrations in 

 different water masses depend upon the previous biological his- 

 tory of the waters (15). Most trace elements known to effect 

 the metabolism of bacteria and higher organisms occur in sea 

 water in concentrations ranging from 0.1 to 50 /xg/Hter. 



TABLE 2 



Major Constituents, Exclusive of Gases, in Solution in Ocean Water 



OF Salinity (S%(,= 35.00 at pH 8.0: Computed From Data of 



Lyman and Fleming (33) 



Concentrations as well as the molecular organization of car- 

 bon, nitrogen, oxygen, phosphorus, silicon, and sulfur influence 

 and are influenced by biological activities; microorganisms are 

 particularly important in this respect. The concentrations of plant* 

 nutrients, notably compounds of nitrogen, phosphorus, and sili- 

 con (required for the skeletons of diatoms and radiolarians ) , 

 vary considerably in time and space (2), being affected by bio- 



