waters at depths of 400-800 m, the values of destruction, 

 to ^^C and ATP data, increase to 3-5, in the layer of the 



1971). Experiments have shown that the bacterial activity in deep 



samples (from 3000-4000 m) upon exposure of the samples in situ , is low 



even when the samples are enriched with easily assimilated organic 

 matter (Fig. 16). 



The rate of biochemical decomposition (respiration) in deep waters, 

 expressed in units of oxygen consumed, according to the results of 

 physical and chemical calculations (Riley, 1951; Munk , 1966; Arons , 

 Stommel , 1967) and measurements of the concentration of ATP and ETS 

 (electron transport enzymes) in the plankton yield values of 

 decomposition in deep waters of 0.01-0.06 mg 02/m per day (Strickland, 

 1971; Hobbie et al . , 1972). This rate of destruction corresponds to an 

 oxygen consumption of 0.1-0.2 mg/1 yr. With this rate of destruction, 

 the reserve of oxygen in descending Antarctic waters should be 

 sufficient for 50-100 years. 



Direct analyses of the intensity of the destruction in the "old" 

 deep waters in the central part of the Pacific by the -^ C method have 

 yielded quantities close to the calculated quantities (Table 7). In the 

 deep waters of the Western Pacific, where, according to the model of 

 global circulation (Kuo, Veronis, 1970) the primary flow of meridional 

 advection of Antarctic water occurs, the values were 3 to 6 times higher 

 (Sorokin, 1971a). In the upper layer of the intermediate Antarctic 



according 

 ^e bacterial 



maximum at a depth of 500-550 m- to 10-20 mg 02/m-^ per day. With this 

 intensity of destruction, we should see a shortage of oxygen at this 

 level within 1-2 years, which does actually occur (Fig. 17). These data 

 indicate that the shortage of oxygen ordinarily observed in intermediate 

 waters is formed primarily as a result of local consumption of O2 by 

 microflora which have a constant maximum of activity here. 



The rate of decomposition in the surface waters of the pelagic zone 

 of the oceans is 20-30 mg 02/m-^ per day in oligotrophic waters, 50-200 

 mg 02/m'^ per day in mesotrophic and eutrophic waters. 



Determination of the potential destruction (long-term exposure of 

 samples at 20-30°C) by the ^'^C and BOD methods yield values of 0.15 mg 

 O2/I , both in deep and in surface samples (Sorokin, 1971a, 1973c; 

 Novoselov, 1962). The BOD rate constant in surface waters of the ocean 

 is 0.02-0.10, close to the constant of the rate of destruction of 

 phytoplankton in sea water (Skopintsev, 1966; Finenko, Ostapenya, 1971; 

 Ogura, 1972). 



The rate of bacterial destruction of organic matter in the bottom 

 sediments of the seas can also be characterized by the rate of oxygen 

 consumption, since biologic oxidation of organic matter in sediment, 

 performed primarily by microflora, significantly predominates over 

 chemical oxidation. The rate of destruction of organic matter in bottom 

 deposits, based on averaged data for various biotopes and the integral 

 values of destruction beneath each square meter in a layer 5 cm thick 

 (considering the nature of distribution of bacterial activity in the 

 sediment) are presented in Table 8. In the sediment of the neritic 

 zone, 1 g of silt absorbs about 0.1 mg 02/day. The annual destruction 



269 



