experiments showed that oysters, polychaetes, sponges and ascidians are 

 capable of normal feeding on bacterioplankton at its natural 

 concentration. Their nutrition in this case is no less than it would be if 

 they fed on fine phytoplankton. The filtering rate was 200-600 1/g of 

 organic carbon in the body of the animals per day. It was found that coral 

 polyps can also consume bacterioplankton (Sorokin, 1972, 1973a, b, e). The 

 capability of coral to digest the bacteria they consume was proven by 

 measuring the radioactivity of CO2 liberated by them after feeding on 

 labeled bacteria. 



One important intermediate trophic link allowing the utilization of 

 bacterioplankton in the food chain are the Protozoa: the ciliates 

 (Tintinnidae, Strombidium ) and the colorles flagellates such as Bodo 

 (Fenchel, 1970; Fenchel , Reidl, 1970; Johannes, 1965; Petipa et al . , 

 1974). The protozoans consume bacteria and themselves serve as food for 

 the crustacean micro- and mesozooplankton (Mordukhay-Boltovskaya, Sorokin, 

 1965; Monakov, Sorokin, 1971; Pavel 'yeva, Sorokin, 1971). In the boreal 

 sea basins, the Protozoa develop in mass after the decay of phytoplankton 

 at the end of the spring bloom which cause an increase of the biomass of 

 bacteria. The biomass of ciliates and colorless flagellates may reach 

 1 g/m^ in the open sea in the layer of the main maximum up the thermocline, 

 exceeding the biomass of the remaining zooplankton. Massive development of 

 bacteria and Protozoa represents an important stage in the heterotrophic 

 phase of the seasonal succession of the plankton community in the temperate 

 waters. During this period, they are actively consumed by calanoids 

 (Sorokin, 1974). The Protozoa are one of the leading components in the 

 plankton community of the regions of upwellings (Beers, Stewart, 1971; 

 Tumantseva, Sorokin, 1975). 



As was noted above, bacteria and Protozoa represent the main 

 nutritional component of detritus and of the bottom sediments. Direct 

 microscopic observations (Newell, 1965; Fenchel, 1972) have shown that in 

 the detritus which passes through the intestines of benthic animals, the 

 population of bacteria is decreased several times due to digestion (Newell, 

 1965; Johannes, Satomi, 1966). Experiments with ^T have proven the 

 digestion of bacteria by amphipod sestonophages (Hargrave, 1971). 

 Holothurians and gastropods digested the labeled microflora in the bottom 

 sediments available to them, which provided them with a normal ration 

 (Sorokin, 1972). 



Direct correlation in the distribution of the biomass of bacteria and 

 meiobenthos in the oceanic benthic sediment (Table 11) indicates that the 

 bacteria represent the main nutritional component of the meiobenthos. 

 Actually, the microflora in the sediment forms the predominant portion of 

 the living available protein. In deep-water sediments of the oligotrophic 

 areas of the oceans where the concentration of microflora is very low there 

 are no benthic animals which nonselectively swallow the bottom (Sokolova, 

 1972). 



An overall evaluation of the trophic significance of the microflora 

 can be produced only at the level of the ecosvstem by calculating the 

 fraction of its participation in the transformation of matter and energy of 

 the entire community. In order to produce the corresponding information, 

 microbiologic analyses should be conducted in combination with 



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