The nature of all aquatic environments depends upon the following factors which exert their effects in varying degree:
i) The depth of water
Has an important secondary effect by reducing the penetration of light and hence the degree of colonisation by plants.
ii) Light
Water absorbs light of long wavelengths, particularly the blue part of the visible spectrum. Since this would not normally be sufficient for photosynthesis, many freshwater plants possess adaptations so that light does not become a limiting factor in their growth.
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