increase as greater quantities of petroleum are trans- 
ported; however, with fewer (although larger) ships, 
the probability of an accident decreases and the net 
results are uncertain. If there were a supertanker 
casualty, the potential spill could be of major pro- 
portions and affect both living and nonliving marine 
resources, as well as the recreational use of coastal 
areas. 
All pollutants are not chemical or particulate in 
nature. Energy conversion is exothermic, and large 
amounts of heat energy are transferred to the aquatic 
environment in the production of electrical energy 
and in other industrial activities. Coastal regions at- 
tract industries that require large quantities of cooling 
water. If discharged into confined estuaries, the waste 
heat can be considered a pollutant to the extent that 
it adversely affects the productivity of the marine 
environment. In some instances, thermal enrichment 
can prove beneficial by increasing marine pro- 
ductivity. 
The rate of ocean pollution has increased with 
Fertilizers 
Remote Sources 
— Natural 
— Pollutant 
® Local Sources 
— Natural 
— Pollutant 
population density and societal affluence, which were 
not accompanied by recognition of pollution as a 
priority issue. The increasing production of energy 
and conversion of materials to consumer goods are 
the basic causes of pollution. Thus, the industrially 
developed nations of the world, generally in the 
Northern Hemisphere, are the prime sources of en- 
vironmental pollution. In the past, man turned to the 
oceans for waste disposal because costs of land and 
transportation were rising and it was more economi- 
cal to dump wastes in the ocean, particularly the 
wastes of coastal cities and industrial centers; be- 
. cause dumping in the ocean involved fewer political 
conflicts; and because people believed the ocean had 
an infinite capacity to absorb such wastes. With our 
better understanding of the ocean’s physical, chemi- 
cal, and biological processes—its interactions with 
the atmosphere and adjoining lands, and its mechan- 
isms of mixing, transport, and exchange—we now 
know that the ocean cannot accept unlimited pollu- 
tants without affecting our well-being (fig. 6-1). 
@ Dissolved 
@ Particulate 
— Inorganic 
— Organic 
Sewer Outfalls 
@ Industrial 
— Dissolved 
— Particulate 
© Municipal 
— Dissolved 
— Particulate 
Ocean Dumping 
Excavation 
Dredged Material 
Sewage Sludge 
Industrial Wastes 
— Solid 
— Liquid 
Figure 6—1.—Chemical enrichment of the ocean 
VI-2 
