the microflora; the regeneration of inorganic forms of nitrogen and 

 phosphorus during the course of oxidation of organic matter by 

 microflora; the oxidative transformation of ammonia and urea into 

 nitrates; the fixation of atmospheric nitrogen, achieved by the energy 

 of oxidation of organic matter; processes of regulation of the content 

 of dissolved organic matter (DOM) and suspended organic matter in sea 

 water by the activity of microflora inhabiting the surfaces of suspended 

 particles (DOM-suspension system); accumulation and precipitation of 

 biologically active metals (Fe, Mn, Co, certain trace elements) after 

 they are included into the bacterial biomass and subsequently introduced 

 into the food chain; the synthesis of organic forms of phosphorus and 

 nitrogen from inorganic forms upon oxidation of organic matter by the 

 microflora. 



Let us analyze the available data on the intensities and mechanisms 

 of these processes. 



2.6 Intensity of Microbial Decomposition of Organic Matter and 

 Consumption of Oxygen in the Water and in Sediments 



The total concentration of organic matter in the water of the ocean 

 is 1.5-2.5 mg C/1, or about 15 kg/m^ of dry organic matter. About 60% 

 of this matter is represented by the relatively stable fraction of 

 aqueous humus (Skopintsev, 1966; Ogura, 1972), the remainder--by low- 

 molecular components: amino acids, fatty acids, carbohydrates (Duursma, 

 1965; Khaylov, 1971; Andrews, Williams, 1971). The absolute content of 

 organic matter, its composition, the content of the available fraction 

 of DOM and suspended matter, determined by the potential BOD 

 (biochemical oxygen demand) or the potential production of bacteria 

 (Fig. 15), change relatively little right up to very great depths 

 (Novoselov, 1962; P. M. Williams, 1969; Starikova, Korzhikova, 1970; 

 Finenko, Ostapenya, 1971; Sorokin, 1971a, d,g; Menzel , 1978). These data 

 contradict the traditional concept of the predominance of inert aqueous 

 humus at great depths, which was set forth at one time to explain the 

 extremely low BOD in the deep waters of the ocean. It was based on the 

 concept that the source of replenishment of organic matter in the deep 

 water consists of the remains and excrement of the plankton sinking down 

 from the higher layers. 



According to modern concepts, the deep and intermediate waters are 

 formed of productive surface waters descending at the convergences in 

 the high latitudes, then drifting in the direction of the equator. In 

 the zones of the tropical divergences, they rise and are redistributed 

 by the equatorial currents (Stommel, Aarons, 1960; Veronis, 1972). In 

 accordance with this model, the main path of penetration of organic 

 matter into the deep and intermediate waters is its horizontal transfer 

 from the productive high-latitude regions (Redfield, 1942; Wyrtki, 

 1962). This mechanism explains fully a relative uniformity of 

 distribution of organic matter in the water column described earlier. 

 The low actual values of BOD are explained not by the great stability of 

 organic matter in the deep waters (which has not been confirmed by 

 recent studies), but rather by the unfavorable conditions for the 

 functioning of deep-water microflora; the joint inhibiting effect of low 

 temperature and high pressure (Sorokin, 1969, 1971c; Jannasch et al . , 



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