Cyanophyceae, also known as cyanobacteria or blue-green algae, constitutes a phylum of photosynthetic bacteria found in diverse aquatic and terrestrial habitats. The term "cyanophyceae" derives from the Greek words "kyano" (blue) and "phyceae" (seaweeds), named after their distinctive bluish-green pigmentation and algae-like characteristics.
These microorganisms are characterized by their prokaryotic cellular structure, lacking a nucleus and membrane-bound organelles. They possess an intricate prokaryotic cell wall, known as a peptidoglycan layer, providing protection and maintaining their shape. Cyanophyceae engage in oxygenic photosynthesis, utilizing pigments such as chlorophyll-a and phycocyanin to capture light energy and convert it into chemical energy.
Cyanobacteria are essential contributors to global carbon and nitrogen cycles, playing a fundamental role in primary production. They can convert atmospheric nitrogen gas (N₂) into soluble forms such as ammonia (NH₃) through a process called nitrogen fixation. This conversion facilitates the availability of nitrogen, a crucial nutrient for other organisms in the ecosystem.
Furthermore, some cyanobacteria form symbiotic relationships with other organisms, such as lichens and corals. They contribute to the health and stability of these ecosystems by providing photosynthetic products and fixing nitrogen.
However, certain cyanobacteria species can produce toxic compounds called cyanotoxins under certain environmental conditions, leading to harmful algal blooms (HABs). These blooms have negative impacts on human and animal health, as well as the environment.
Overall, cyanophyceae encompass a diverse group of prokaryotic organisms with significant ecological importance, contributing to both beneficial and detrimental
