phosphates and dissolved oxygen in the water which have been observed. 

 Their distribution is related not only to local processes of 

 mineralization, but also to the global oceanic circulation. The most 

 acceptable solution is the assumption that processes of mineralization, 

 leading to the generation of mineral phosphate and the formation of the 

 oxygen minimum, occur in the intermediate Antarctic waters along the path 

 from the region of their formation (at the Antarctic convergence) to the 

 equator. The substrate of the destruction is the organic matter of the 

 productive surface Antarctic waters descending in the zone of convergence 

 (Wyrtki, 1962; Redfield et al . , 1963). This plan is confirmed by data on 

 the intensification of bacterial destruction at the upper boundary of the 

 Antarctic waters (see Fig. 17). As we noted earlier, the intensity of the 

 process of destruction is sufficient to form an oxygen minimum and result 

 in regeneration of nutrients in 1-3 years. 



The concentration of organic phosphorus in the surface topical waters 

 of the ocean is 0.2-0.4 yg-atom/1 , or 60-80% of the total phosphorus. 

 Therefore, the processes of local bacterial mineralization of this reserve 

 of nutrients, consisting primarily of the stable soluble fraction, are of 

 geat significance in the provision of biogenic nutrition for the 

 phytoplankton. Ammonia is formed as a result of mineralization of organic 

 forms of nitrogen by bacteria. In regions where the surface waters are 

 poor in nutrients, it is consumed by the phytoplankton before it is 

 oxidized to nitrate. In oligotrophic tropical waters, up to 99% of the 

 mineral nitrogen is utilized by the phytoplankton in the form of NHt 

 (Dugdale, Goering, 1967). A portion of the ammonia nitrogen, formea as a 

 result of mineralization, is oxidized to nitrites and then to nitrates by 

 the nitrifying bacteria (Watson, 1963; Carlucci, McNally, 1969). It is 

 presumed that the nitrates of the deep and intermediate waters are formed 

 due to oxidation of ammonia in the regions of the high-latitude 

 convergences, where they submerge with the descending waters (Dugdale, 

 1969). 



2.8 Significance of Microbial Biosynthesis in the Cycle of Some 

 Mineral Elements" 



A large-scale biogeochemical process of production of microbial 

 biomass in the ocean involves carbon plus other elements, which are 

 included in the composition of the protoplasm of the microorganisms: 

 nitrogen, phosphorus, iron, trace elements. Data are presented above on 

 the scale of involvement of inorganic phosphate into the bacterial 

 synthesis. As concerns nitrogen, the situation should be similar, 

 particularly with oxidation of organic matter by the microflora in deep 

 waters and in bottom sediment, but this process is poorly studied. It has 

 been shown that the marine microflora can cause nitrification and inclusion 

 of molecular nitrogen into biosynthesis (Maruyama et al . , 1970; Pshenin, 

 1966). However, it is very difficult to make a distinction between 

 nitrification of bacteria and of blue-green algae. The total nitrification 

 in the sea may exceed 300 g/ha«day (Dugdale, Goering, 1964). 



Experiments involving the use of the radioisotopes of iron and cobalt 

 have shown that iron is consumed by bacterioplankton at a rate of 0.5 ug 

 per mg of organic carbon of the bacterial biomass produced. Cobalt is 

 consumed by marine bacterioplankton for the synthesis of vitamin 6,0 i" the 



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