Question

The sources of dissolved oxygen in water is ________________.
A. photosynthesis
B. natural aeration
C. mechanical aeration
D. all of the above

Answer 1

Hint: Dissolved oxygen in water plays a vital role for aquatic life. This is because the dissolved oxygen is used by the aquatic animals for breathing. There can be a lot of sources for this as it depends on the environment of that atmosphere.

Step by step answer: The oxygen in the water gets dissolved from the various sources i.e. the atmosphere and the process of photosynthesis performed by the aquatic plants.
Photosynthesis- Photosynthesis is a process by which green plants convert carbon dioxide and water in the presence of light energy into sugar and oxygen.
\[6C{O_2} + {\rm{ }}6{H_2}O + light{\rm{ }} \to {C_6}{H_{12}}{O_6}{\rm{ }} + {\rm{ }}6{O_2}\]
The aquatic plants like algae or phytoplankton use the light energy to perform the process of photosynthesis to produce oxygen. This oxygen gets dissolved in the water. Therefore, the process of photosynthesis performed by aquatic plants act as the primary source of dissolved oxygen.
Also the oxygen gets dissolved through the process of aeration. Aeration is the process by which oxygen is added to the water bodies from the atmosphere. This may be of two types either natural or mechanical. Natural aeration involves the introduction of oxygen and removal of unwanted harmful and toxic gases like carbon dioxide etc. to maintain the quality of the water. Whereas the mechanical aeration involves the use of machinery and modern methods to introduce the oxygen in the water bodies. It can be done with the help of rotating brushes, paddle wheels, etc. In short we can say that mechanical aeration is the type of aeration in which mechanical energy is used to introduce oxygen to the water.

Hence, option (D) all of the above, is the correct option.

Note: The sources of dissolved oxygen in water are the process of photosynthesis performed by aquatic plants and the atmosphere. The oxygen from the atmosphere gets dissolved in the water by the process of aeration. It must be noted that there are lot of sources which can lead to dissolved oxygen in the water, it may help in the aquatic conservation.