Dissolved Oxygen

Oxygen is necessary for fish life to make available energy contained in food. The atmosphere is having 21-23 percent oxygen at sea level.

Source of oxygen in water: Oxygen dissolves in water and occurs as a simple solution. It does not combine chemically with water.

Oxygen diffusion is of minor importance. The rate at which oxygen diffuses into water is governed by physical laws which relate to the solubility of gases. Rate of diffusion can be increased by agitation (aerators) which allows more contact of surface water with air.

Photosynthesis is the single most important source of oxygen in pond water. All green plants manufacture food by a process called photosynthesis during day time with the help of sun light. Plants use nutrients (N, P, K, etc.), carbon dioxide (C02), water (H20), and energy from sunlight to make their food. A waste product of this process is oxygen which is given off and is dissolved in the water.

Oxygen cycle: The oxygen concentration in water changes from minute to minute depending on many factors but essentially it follows a definite pattern during any 24-hour period.