microrganismi

Microrganismi, often called microorganisms, are microscopic organisms that are too small to be observed with the naked eye. They include cellular forms such as bacteria, archaea, fungi, and protists, and, in some classifications, acellular agents such as viruses.

They vary widely in size, typically ranging from about 0.2 micrometers to a few hundred micrometers, while viruses are generally about 20 to 300 nanometers in diameter. They inhabit virtually every environment on Earth, including soil, water, air, and the bodies of plants and animals.

Microrganismi play essential ecological roles, including nutrient cycling (carbon, nitrogen, sulfur), photosynthesis (in cyanobacteria and algae), and organic matter decomposition. They are also used by humans in processes such as fermentation, antibiotic production, and bioremediation. Many form symbiotic relationships, such as gut microbiota that aid digestion and immune function. Pathogenic microorganisms can cause diseases; others are benign or beneficial.

Study and application rely on microscopy, culture methods, and molecular techniques such as DNA sequencing and metagenomics. A substantial fraction of microbial diversity remains uncultured, which challenges understanding and exploitation. Proper biosafety practices are essential when handling microorganisms due to potential health and environmental risks.