decrease in the intensity of photosynthesis of plants, an increase in 

 oxygen consumption in animals due to intensification of metabolism 

 (which, when the oxygen content of the water is reduced, has a harmful 

 influence on them), an increase in the susceptibility of local species 

 of animals and plants to various toxic substances and pathogenes, 

 possibly causing massive death of species. As a result of the 

 stagnation of water caused by thermal pollution, there may be cases of 

 massive development of algae and, consequently, processes of decay, 

 which have a depressing effect on many species. Thus, thermal pollution 

 disrupts the normal ecologic balance of communities inhabiting the 

 natural waters in the area of the thermal discharge. 



For example, in Chesapeake Bay, under the influence of thermal 

 pollution, a population of commercially valuable soft-shell clam. My a 

 arenaria , died and was replaced by the small, noncommercial species 

 Gemma gemma , which has a higher level of heat tolerance (Kennedy, 

 Milhursky, 1971). In the region of Cape Cod, thermal pollution, on the 

 other hand, stabilized the population of the mussel Hytilus edulis , by 

 depressing the feeding of its primary enemies--the sea star Asterias 

 forbesi , the dog-whelk Thais lapillus and the crab Carcinus maenas 

 (Pearce, 1969). 



The decrease in the population of the bivalve Mulinia lateralis in 



the waters of the Atlantic coast of the USA, resulting from thermal 



pollution, has significantly harmed water birds, for which it was a diet 

 staple (Kennedy et al . , 1974). 



3.3 Influence of Thermal Pollution on the Distribution of Flora 

 and Fauna" 



Benthos . --Examples of the influence of thermal pollution on the 

 benthos have been accumulated for some time, primarily for various areas 

 along the Atlantic coast of the USA. In the estuary of the Patuxent 

 River and a number of other areas of the Chesapeake Bay, thermal 

 discharges have greatly decreased the areas of the plant Ruppia 

 maritima , while increasing the biomass, population and density of 

 epifauna' (Anderson, 1969; Cory, Nauman, 1969; Nauman, Cory, 1969). In 

 Biscayne Bay, thermal pollution caused disease, then death of blooming 

 plants and macrophytes and changes in the composition of the zoobenthos 

 (Roessler, zieman, 1969; Wood, Zieman, 1969; Thornhaug et al . , 1973). 

 In other areas of the Florida coast, thermal pollution has been found to 

 influence the distribution and migration of the commercial blue crab 

 Callinectes sapidus (Nugent, 1970; Leffler, 1972). 



In one bay along the California coast, in a heated area, the 

 species variety of bivalve mollusks increased, while in other bays the 

 composition of benthic communities changed (North, 1968). 



Thermal pollution in Hawaii caused the death of corals in the 

 region of the thermal discharge and the transformation of the reef to 

 dead limestone covered with sand (Jokiel, Coles, 1974). Changes in the 

 benthos of the Baltic Sea coastal area, observed by Swedish 

 investigators in an area of thermal discharge from a 3 million kW 

 nuclear power plant were similar to those observed in natural waters 



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