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THE VALUES TO BE PROTECTED 
MARINE ECOLOGICAL SYSTEMS 
Components of An Ecosystem 
As was pointed out by Boyd et al. (1972), the ultimate concerns associated 
with impacts of the dredging-disposal process are the direct and indirect 
_ effects on biological communities. It should be added, however, that these 
community changes have the potential for impacting the welfare of man. 
All ecosystems are major functional organizations involving both living and 
non-living components. The living components include the various groups of 
plants and animals that make up the biological communities. The non-living 
components are the atmosphere above the water, the water column, and the 
sea floor that collectively comprise the environments of the living sys- 
tems. The living and non-living components of ecosystems are bound togeth- 
er through the dynamic exchange and recycling of chemical material and 
energy, and the patterns of such exchange are determined largely by the 
controlling factors of the physical and chemical environments. 
Non-Living Components 
The atmosphere above the ocean water is of primary importance because water 
mass movement is induced largely by the frictional force of winds passing 
over the water surface. Wind-driven currents play a major role in the 
horizontal spread of organisms and of any materials discharged at sea. The 
atmosphere is also an important source of oxygen that dissolves in the 
water and sustains life even at great depths. 
The water column itself provides the conditions of light, temperature, 
salinity, nutrient concentrations, density, and pressure to which the or- 
ganisms must adjust if they are to survive in a given area. The seasonal 
progression of the sun determines that greater amounts of heat and light 
will be received by the surface waters during late spring, summer and early 
fall than during the remaining seasons, when the sun is more directly over 
the southern hemisphere. Much of the sunlight striking the sea surface is 
