What happens to dissolved oxygen (DO) levels when temperature decreases?

When the temperature decreases, the solubility of oxygen in water increases, which means that dissolved oxygen (DO) levels actually increase. Cooler water has an enhanced capacity to hold oxygen compared to warmer water. This principle is critical in aquatic environments where temperature fluctuations can affect oxygen availability for aquatic life.

As the temperature drops, organisms in the water may benefit from the higher levels of dissolved oxygen, which is essential for their survival. Understanding this relationship is crucial for managing On-Site Sewage Facilities (OSSF) and ensuring that the treatment processes maintain adequate oxygen levels to support microbial activity and the health of the surrounding environment.