The Fundamentals of Water and Natural Waters

Background

When viewed from a spacecraft, the Earth appears as a shining blue and white orb. The blue light is reflected from the water of the ocean and the white light from the condensed water vapor of the clouds. Water is the dominant and defining feature of our planet. Not surprisingly, water is also one of the defining features of life.

Figure 1.

View of Earth from space taken by Apollo astronauts on December 7, 1972.

http://en.wikipedia.org/wiki/The_Blue_Marble#mediaviewer/File:Apollo17WorldReversed.jpg

The Earth formed some 4.5 billion years ago. The ocean appeared about 1 billion years later (Stanley, 2009). From that primordial sea evolved the first forms of life about a half a billion years later. So for most of its existence Earth has been wet and alive. Water shaped the forms of life that evolved in the sea and eventually invaded the land. And as life developed it reshaped the nature of the ocean and atmosphere above. About three billion years ago the process of photosynthesis developed in certain bacteria and algae. This new type of metabolism used energy from sunlight to fuel these early plant-like creatures. To access the energy in sunlight, photosynthesis splits water molecules resulting in the release of free oxygen as a waste product. That oxygen changed the chemistry of the sea and the air. The splitting of water also produces high-energy electrons and protons that are used in photosynthesis to do the work of the cell, including building sugars from atmospheric carbon dioxide (Garrison, 2001). Algae use sugars made in photosynthesis as the basis to create a huge variety of organic compounds. Those organic molecules fuel the rest of the ocean food chain, and a portion of them is buried in the ocean sediments. Over time those buried organic molecules transform into petroleum and natural gas that now fuel much of our economy. Indeed, it is the burning of millions of years’ worth of fossil fuels over the last two centuries that is once again changing the atmosphere and the global climate (Miller & Spoolman, 2014).

The Structure Of Water And Its Chemestry

Water is a wondrous substance. Its special structure gives rise to a variety of important properties the reader will need to understand in order to appreciate subsequent chapters. Water is a molecule made up of two different kinds of atoms, oxygen and hydrogen. Mostly water appears as H₂O, one larger oxygen molecule sharing electrons with two smaller hydrogen atoms. The sharing of electrons by the oxygen and hydrogen atoms results in what are called covalent bonds (Becker & Wentworth, 1973).