Microorganisms are invisible without a microscope. In addition, you cannot taste or smell germs like bacteria in contaminated food. However, the odour of bacteria metabolising perspiration is detectable. Additionally, toenail fungus infections emit an odour.
While all bacteria and archaea are microorganisms, only some fungi and algae fall into this category. Microscopic creatures include rotifers and the vast majority of protozoa. The microscopic organisms inhabit soil, the atmosphere, the ocean floor, and the interior of rocks. In ecosystems, decomposition and nutrient recycling are aided by microorganisms. Microorganisms in the atmosphere may influence precipitation and weather. Other organisms participate in the nitrogen cycle.