Dissolved Oxygen and Redox Potential

Abstract

The atmosphere is comprised of nitrogen, oxygen, argon, carbon dioxide, water vapor, and traces of a few other gases. These gases are soluble in water, and an equilibrium state can be reached between atmospheric gases and dissolved gases. Dissolved oxygen is the most important gas in water quality because it is essential in aerobic respiration and it regulates the oxidation-reduction potential in water and sediment. Carbon dioxide is a waste product of respiration, a source of carbon for photosynthesis, and a major determinant of pH in natural waters. Dissolved nitrogen usually has a higher concentration in water than other gases, but its influence on biological and chemical processes is less than that of oxygen or carbon dioxide. Other gases usually have little influence on water quality.