What may happen to dissolved oxygen levels in warmer water?

Dissolved oxygen levels tend to decrease in warmer water due to the physical properties of gases. As water temperature rises, the solubility of oxygen decreases, meaning that warmer water can hold less dissolved oxygen compared to cooler water. This phenomenon occurs because gas molecules are less soluble in warmer liquids; as temperature increases, the kinetic energy of the molecules also increases, leading to a reduction in their interaction and bonding with water molecules.

In aquatic environments, this reduction in dissolved oxygen can have significant ecological impacts. Many aquatic organisms, such as fish and invertebrates, rely on sufficient dissolved oxygen levels for respiration. Therefore, when water temperature rises, it can lead not only to reduced oxygen availability but also to stress on aquatic life and potential shifts in the ecosystem structure.

The other answers do not accurately reflect the behavior of dissolved oxygen in relation to temperature changes. In cooler water, oxygen levels can remain higher and more stable due to increased solubility. The idea that dissolved oxygen levels would fluctuate rapidly does not consider the consistent relationship between temperature and oxygen solubility, whereas stating they remain constant ignores the direct correlation to temperature changes.