Here are some facts about oxygen in water:

 Here are some facts about oxygen in water: 

Solubility

Oxygen is poorly soluble in water, and its solubility depends on temperature and pressure. Colder water can hold more oxygen than warmer water. For example, at 0 °C, freshwater can dissolve 14.6 mg/L of oxygen, while at 25 °C it can dissolve only 7.6 mg/L.

Sources

Oxygen enters water through a number of processes, including: 

Wind: Winds aerate the water's surface, dissolving oxygen from the air. 

Photosynthesis: Aquatic plants produce oxygen as a byproduct of photosynthesis. 

Turbulence: Water that tumbles over rocks, such as in waterfalls, rapids, and riffles, dissolves oxygen from the air. 

Health

Healthy water has dissolved oxygen concentrations between 6.5–8 mg/L. When dissolved oxygen levels are too low, fish and other aquatic organisms can't survive. 

Factors that affect oxygen levels

In addition to temperature, other factors that affect oxygen levels include: 

Salinity: Fresh water can absorb more oxygen than salt water. 

Bacteria and algae: When algae die, bacteria consume them and the oxygen dissolved in the water. This process is called biochem

ical oxygen demand.