Schizophyceae is a group of unicellular photosynthetic bacteria commonly known as cyanobacteria. Some synonyms for Schizophyceae include blue-green algae, blue-green bacteria, and cyanophytes. The term "blue-green" is used to describe the color of these bacteria, which is due to the presence of pigments called phycobilins. Cyanobacteria are found in a variety of habitats, from freshwater lakes and rivers to saltwater oceans and even desert crusts. They are important producers of oxygen and play a significant role in the global carbon cycle. However, some cyanobacteria are also known for producing harmful toxins, which can have negative impacts on human health and the environment.