Emitting light through a series of chemical reactions by certain living organisms is called

Bioluminescence

Explanation:

Bioluminescence is a phenomenon of light emitting by a living organism caused by set of chemical reaction within that organism. The reaction in which light is a final product involves light-emitting molecule such as luciferin and enzyme such as  luciferase that reacts with it (causes the oxidation of the luciferin). Luciferin can be produced by organisms themselves or can be absorbed from the food.

Usually marine organisms have the ability to produce light, but this reaction might occur in some bacteria and fungi.