464 
below 1000m) and, at least, for food production will not be used to a 
greater degree in the future. This is a view that is shared by the 
distinguished Russian oceanographer P. A. Moiseev (1971) as well as many 
fisheries experts. 
Some marine scientists oppose the disposing of dredged material on the con- 
tinental slope because of the fear that the rapid introduction of substan- 
tial volumes of sediment would produce catastrophic impacts. But certain 
natural occurrences in the form of turbidity flows or currents provide some 
information on the effects of rapid sediment introduction to the ocean 
floor. Turbidity flows are known to be a common occurrence on some conti- 
nental slopes. Obviously, such flows will kill some animals and transport 
others to greater depths where they may not be able to reproduce, but there 
apparently are compensating factors. For instance, Griggs et al. (1969) 
found that the Cascadia Channel (2600m depth) off the coast of Oregon and 
Washington had been receiving numerous postglacial-age turbidity flows. 
Yet the benthic animal populations in the flow areas were four times as 
abundant as those on the adjacent Cascadia Abyssal Plain that has not been 
affected by such flows. It was postulated that the turbidity flows in- 
creased the utilizable organic material in the sediment, thereby enhancing 
the deep ocean environment. 
Thus, even though there-have been very few truly deep ocean disposals of 
dredged material that have been studied from the standpoint of impacts on 
the biota, there is an impressive amount of indirect evidence that the im- 
pacts in the deep ocean will not have serious effects on the benthic life. 
Although it is believed that much of the offshelf region of the world ocean 
is suitable for dredged material, there are particular types of features of 
the deep ocean that will lend themselves well to the assimilation of pol- 
luted material. 
