Class Cyanophyceae, commonly known as cyanobacteria, is a taxonomic class of prokaryotic microorganisms that belong to the phylum Cyanobacteria. They are characterized by their ability to perform oxygenic photosynthesis, which involves the conversion of light energy into chemical energy using water as an electron donor and releasing oxygen as a byproduct. Cyanobacteria are an ancient group that played a crucial role in the oxygenation of Earth's atmosphere.
Members of the class Cyanophyceae are typically unicellular or filamentous, and they can be found in various environments including freshwater, marine, and terrestrial habitats. They are widely distributed globally, ranging from hot springs and polar regions to deserts and deep oceans.
Cyanobacteria have a unique cellular structure. They lack a membrane-bound nucleus and other membrane-bound organelles, instead having a region called the nucleoid that contains their genetic material. Their cell wall is composed of peptidoglycan and sometimes additional polysaccharides.
Cyanobacteria colonies often exhibit diverse morphologies and can form specialized structures called heterocysts, which are nitrogen-fixing cells, and akinetes, which are resting cells resistant to adverse conditions. Additionally, they can produce pigments, such as phycocyanin and chlorophyll, giving them a range of colors from greenish-blue to red.
Cyanobacteria are autotrophic organisms that are vital to ecosystem functioning. They play a significant role in primary production, carbon cycling, nutrient fixation, and nitrogen recycling. Some species also form symbiotic relationships with plants, lichens, or fungi. Moreover, cyanobacteria contribute to the production of harmful algal blooms, which can have detrimental effects on aquatic ecosystems and human health.
