Why does cold water have good dissolved oxygen (DO) levels?

Cold water has good dissolved oxygen (DO) levels primarily because the solubility of gases, including oxygen, increases as temperature decreases. This means that colder water can hold more dissolved oxygen than warmer water. The molecular activity in colder water is slower, allowing gas molecules to be more effectively captured and retained within the water.

As the temperature of water rises, its capacity to hold dissolved gases diminishes. This is an important concept in aquatic ecosystems, as higher levels of dissolved oxygen are essential for the health and survival of aquatic organisms such as fish and invertebrates. Thus, the colder the water, the higher the potential for dissolved oxygen levels, making it a crucial factor for maintaining healthy aquatic environments.