Carbon Dioxide

Carbon dioxide is another active compound that dissolves well in seawater. As a result, seawater contains a concentration of carbon dioxide far exceeding that found in air. In its normal concentration in the atmosphere, carbon dioxide is odorless, colorless and tasteless, though in high concentrations, it has an acid odor and taste. This is what gives a carbonated beverage its distinct smell and taste, and why the same beverage tastes different after it “goes flat.”

One of the main sources of carbon dioxide is the waste product from animal respiration (plant respiration in light is called photosynthesis, which consumes carbon dioxide and gives off oxygen). Another important source is air pollution. Divers are primarily concerned with controlling carbon dioxide levels, since, as discussed in Section Two, The Physiology of Diving, too much or too little can cause physiological problems.