J. ASSESSING MAN’S INFLUENCE ON THE OCEANS 
Importance of the Oceans 
The oceans are one of man’s greatest resources. Over seventy 
percent of the earth’s surface is covered by seas. The interaction of 
these areas with the atmosphere is a major determinant of our weather. 
Man depends on the oceans as a major source of his food supply. 
Ocean-going vessels provide a simple and practical means of trans- 
porting large quantities of materials. The oceans themselves are 
essential for man’s existence as nearly all of man’s fresh water supply 
is ultimately derived from the oceans. The ocean resource, like other 
resources, cannot be exploited without limit. 
Definitions 
Contamination and pollution of the oceans are continuing processes 
begun by natural means and heightened by man’s activities. Con- 
tamination is the introduction of any substance foreign to the oceans 
whereas pollution is the addition of a contaminant detrimental to 
ocean use. This often involves a value judgement as to what or how 
much of a contaminant is detrimental. For example, municipal sewage 
can be a health problem or a source of plant nutrients; heated water 
can be fatal to some marine organisms and favorable to others. In 
many cases adequate and reliable data have yet to be gathered to 
enable proper assessment of the effects of ocean pollution. 
There are many ways in which man utilizes marine resources. Many 
of these activities are mutually compatible but some are not. Some 
activities that produced contaminants in the past produce pollutants 
now through an increase in the magnitude of the activities involved. 
With increasing population and technological development, it is 
becoming imperative to develop policies that promote balanced use 
and conservation of the oceans. Without such assessment and planning 
now, there is a high probability that man’s greatest resource, the 
oceans, may become his greatest tragedy. 
Extent of Man’s Influence on the Oceans 
Pollution of the world’s oceans is now possible simply by expansion 
of man’s present activities. For example, disposal of wastes or runoff 
into limited bodies of water is primarily a local problem, and with 
abatement of the pollution, recovery of these bodies is slow but 
possible. With continued discharge, however, there is little hope for 
recovery and the oceans themselves will become polluted. Isolated 
incidents of pollution such as oil spilled or discharged into the ocean 
are local problems, but the sum of many such problems constitutes a 
threat to the entire ocean. Because of the oceans’ size and very long 
mixing cycles, a polluted ocean ultimately poses a threat to man’s 
healthful existence on earth. 
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