cyanobaktérium

Cyanobacteria, often referred to as blue-green algae, are a phylum of bacteria that perform oxygenic photosynthesis. They are found in a wide variety of habitats, including oceans, freshwater, and soil, and are among the most abundant organisms on Earth. Their name comes from the Greek words "kyanos" (blue) and "bakterion" (little staff), referring to their characteristic blue-green color.

These microorganisms play a crucial role in global ecosystems. They are significant primary producers, converting sunlight, water, and carbon dioxide into organic compounds and releasing oxygen as a byproduct. This oxygenic photosynthesis is believed to be responsible for the oxygenation of Earth's early atmosphere, paving the way for the evolution of aerobic life. Some cyanobacteria are also capable of nitrogen fixation, converting atmospheric nitrogen gas into ammonia, a form usable by plants, thus enriching nutrient-poor environments.

Cyanobacteria exhibit diverse morphologies, ranging from unicellular forms to filamentous colonies. They reproduce asexually, primarily through binary fission. While generally beneficial, certain cyanobacteria can form harmful algal blooms (HABs) in eutrophic waters. These blooms can produce toxins that are dangerous to aquatic life, livestock, and humans. Understanding the ecological roles and potential impacts of cyanobacteria is important for environmental management and public health.