What are the sources of dissolved oxygen in water ?

Dissolved oxygen in wate is very important for aquatic life. What process are responsible for the reduction of dissolved oxygen in water ?

The partial pressure of oxygen in air is 0.2 atm. What is the conentration of dissolved oxygen in water in equilibrium with air at 25^(@) C ? ( K_(H) for oxgyen at 25^(@)C is 4.34 cc 10^(4) atm).

What is the significance of dissolved oxygen to the aquatic organisms? How it gets depleted?

Ifthe concentration of dissolved oxygen in water is below X ppm, the growth of fish gets inhibited X is :

More dissolved oxygen is found in?

The Henry's Law constant for oxygen dissolved in water is 4.34xx10^(4) atm at 25^(@)C . If partial pressure of exygen in are is 0.2 atm. Under ordinary atmospheric conditions, calculate the concentration (in moles/litre) of dissolved oxygen in water in equilibrium with air at 25^(@)C .