Principle sources and sinks of oxygen in water

1. Sources

I. Photosynthesis:

• Oxygen production decreases during cloudy days.
• Completely stops at night.
• Gradually decreases as water depth increases and light level diminish.

ii. Diffusion:

• Oxygen is dissolved in water by diffusion from the atmosphere.
• Transfer of oxygen from air to water will occur only when water is unsaturated with dissolved oxygen.
• Diffusion from the atmosphere is aided when turbulence occurs, such as during stormy or windy weather.