Which factor primarily influences the amount of dissolved oxygen in water?

Dissolved oxygen (DO) levels in water are primarily influenced by water temperature. When water temperature increases, the solubility of oxygen in water decreases, which can lead to lower levels of dissolved oxygen. Conversely, cooler water holds more dissolved oxygen. This relationship between temperature and solubility is crucial in aquatic environments, as it affects the health and survival of aquatic organisms that rely on oxygen.

Other factors, such as water flow rate, pH level, and sediment levels, can play significant roles in the overall aquatic ecosystem and may indirectly affect DO levels, but they do not primarily determine the actual amount of dissolved oxygen in the water. Thus, understanding the temperature's impact is essential for managing and maintaining healthy aquatic systems.