Page 7 - Professorial Lecture - Prof Omoregie

It is only in the last first 50 years, that the quest for natural resources to meet the
ever increasing human demands started having considerable impact on the global
environment. Ladies and Gentlemen, it can be said that the human components
of events leading to global warming only started within the last 50 years.

Components of Aquatic Environment
The aquatic environment is conveniently divided into three components (with
salinity ranging from 0.5 to 35%):

 Marine (Seas, Oceans) = Saltwater
 Brackish-water (Estuaries, lagoons) = Region of salt and freshwater
mixing together (intermediary salt concentration)
 Freshwater (Inland waters: Rivers, Springs, lakes, etc) = Low salt
concentration

The ocean derives its names from the Greek word okeanus (occeanus); a word
meaning “outer sea”. The ocean may be defined as the vast body of saline water
that occupies the depressions of the earth’s surface (Garrison, 1998). Over 97% of
the water on the earth surface is contained in the ocean.

Zonation and life in the Marine environment:
The marine environment can conveniently be divided into two broad units:
 Benthic / Substratum
 Pelagic / Oceanic

These two are in turn subdivided into smaller, more convenient categories based
on water depth, light penetration and tidal exposure.

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