Page 3of 24Lecture proper Chapter 5. The Water There are four major habitats in the earth’s biosphere - marine, estuarine, freshwater and terrestrial (Odum, 1971). Water is far more massive and vast in terms of area and volume in comparison to terrestrial habitat. Aquatic environment contain diversified types of vertebrate and invertebrate representatives. To understand more we need to study first the important properties of water. Water as a natural resources: the properties of water The structure of the water molecule creates weak attractions between the oxygen end of one molecule and the hydrogen ends of other water molecules. Even though these ―polar‖ bonds are relatively weak and are constantly breaking and reforming, their existence results in many special properties of water compared to other substances on Earth. These properties of water are largely responsible for life on Earth. Below are natural properties of water - Chemical, Physical, and Biological. Chemical Properties Natural waters always contain dissolved salts, micronutrients, some metals, and gases. In fact, so many substances dissolve in water that it is sometimes (mistakenly) referred to as the "Universal Solvent." While most of these substances are important for healthy aquatic ecosystems, as concentrations increase, they can have negative effects and we think of them as pollutants.