Mikroorganisms

Mikroorganisms, or microorganisms, are microscopic organisms and biological agents that are generally invisible to the unaided eye. They include bacteria, archaea, fungi, algae, and protozoa. Viruses—acellular particles that require living cells to replicate—are often discussed alongside microorganisms, but they are not universally classified as living organisms.

Microorganisms occur in nearly every environment, from soil and water to the bodies of plants and animals, and even extreme habitats such as hot springs or polar ice. They vary in size and form, from bacteria and archaea to single-celled fungi and algae, and in metabolism, using light, chemicals, or organic material for energy.

Ecological and practical importance: Microorganisms drive nutrient cycling and decomposition, support primary production through photosynthesis, and form symbiotic relationships with plants and animals. They are used in food and beverage production, biotechnology, and medicine. Some microorganisms are pathogenic, causing disease, while others contribute to health and environmental resilience.

Study and safety: Microbiology relies on microscopy, culture techniques, and molecular methods such as DNA sequencing and metagenomics. Culturing can bias estimates of diversity; many species resist cultivation. Handling follows biosafety guidelines to prevent accidental release and to address dual-use concerns in research and industry.