Physiology of Finfish and Shellfish

2.1.5. Partial pressure and tension

The tension of a gas in solution is defined as the partial pressure of that gas in atmosphere is in equilibrium with the solution. When the gas pressure over a water sample is reduced gas tend to leave the solution. If we reduce the gas pressure to about half the original value gas leaves the solution until equilibrium is reached when the amount of dissolved gas has reached half its original values.