How do aquatic plants and animals survive in water?
Like other gases, oxygen from the air gets dissolved in water. This dissolved oxygen helps aquatic plants and animals survive underwater.
Here is a simple experiment to show that water contains oxygen.
When water is heated, just before it boils, small bubbles are formed which stick to the inner surface of the vessel. The increase in temperature heats up the air dissolved in water and the hot air tries to escape in the form of bubbles. This proves that air is dissolved in water. This also indicates that oxygen is dissolved in water
Is oxygen present in the soil?
Just like in air and water, oxygen is present in the soil as well. When water is poured on dry soil, a few bubbles are formed on the surface. It clearly indicates that air is present in the soil as well.
Organisms like the earthworm or certain insects that live inside the soil are thus able to obtain oxygen for respiration. It’s only during rains that these organisms come out of the soil. This is because water occupies the space of air in the soil. The air escapes out and this makes it difficult for the organisms to live. That is the reason why these organisms pop out on the surface during rains.
Components of plants like roots also get the required oxygen from the soil.