Micro organisms play an important role in
• maintaining soil fertility, and
• recycling nutrients in ecosystems.
The activities of saprophytic bacteria and fungi convert dead parts of organisms and their wastes into humus which improves soil fertility.
In nature, inorganic substances such as carbon , nitrogen, oxygen, water, phosphates and sulphates are built up into large organic molecules such as proteins and carbohydrates by various Autotrophs including microbial ones. When living organisms die, the elements trapped in these organic compounds are set free, mainly by microbial decomposers, as carbon dioxide, water and ammonia. This sis clearly shown by the role played by micro organisms in the nitrogen and carbon cycles.
