Cyanobacteria

Cyanobacteria are photosynthetic bacteria that contain chlorophyll and other pigments giving them a blueish green tint, which are perhaps best known as pond scum. They can live almost anywhere, and produce oxygen.

Anatomy
Cyanobacteria are commonly known as blue-green algae.. The green color comes from chlorophyll and the blue color from the phycocyanin pigment. For many years they had been classified in the plant kingdom along with algae. Then the electron microscope came along and with that and new biochemical techniques they discovered that they were more like a bacteria than a plant, and are now placed into the kingdom Monera. Different species of these can be brown, red, and yellow. Dense masses of these on water are called blooms. That is where it is said that the Red Sea got its name because of the blooms on its surface. Each cell of cyanobacterium has a thick cell wall, and lack flagella. Some can glide along surfaces, and some can form gas vesicles to float across water. Cyanobacteria is like a circular maze with wall after wall inside them. Then in the center are nucleoids, or circular DNA. Some cells don't have nucleoids, and these are the sites for protein synthesis. Cyanobacteria are about 1 mm. long, and can be sometimes compared to salt lichens. The cells of the cyanobacteria are joined in threads that are surrounded by a mucus producing sheath. The cell threads are widest at the base, and cell threads are often united to form a wad.

Reproduction
Under the right conditions cyanobacteria can reproduce explosively at high speeds to form dense masses called blooms. Some kinds of these blooms can be toxic. Cyanobacteria include both unicellular and colonial species. Colonies can form different shapes, and can even form different cell types. Many cyanobacteria form motile filaments called hormogonia that break away from the main mass to bud and then start new colonies eslewhere. Cyanobacteria reproduce asexually, and some methods are exospores, endospores, akinetes, and hormogonium. In other words cyanobacteria can reproduce by budding, fragmentation, and binary fission. Fission and fragmentation is a form of vegetative reproduction. Photosynthesis plays a big role in reproduction of cyanobacteria. If you have lots of light then they will grow and reproduce very fast, but if you have little light, then they will not thrive. Cyanobacteria perform asexual reproduction by forming thick walled cells. Then the cells divide and gas filled cells are released from the cell thread and drift away.

Ecology
Cyanobacteria that are nitrogen-fixing need only nitrogen and carbon dioxide to survive. They live in soil, mud, and deserts, but are most abundant in lakes, rivers, and oceans. They can also grow over a wide range of temperatures, anywhere from Antarctic lakes under several meters of ice to Yellowstone National Park's hot springs. Cyanobacteria are among the first species to live on bare rock and soil. They have a high tolerance of heat and low pH values unlike green plants. They are often the main autotrophs in hot springs because of their higher tolerance for heat.

Cyanobacteria can also act as endosymbionts in lichens, protists, sponges, and various plants. They help provide energy for the host in these situations. They can even live in the fur of some sloths providing them with camouflage. Cyanobacteria utilize photosynthesis to produce sugar, and are the most abundant photosynthetic organisms on Earth. Cyanobacteria also have the ability to bind and absorb nitrogen surrounding them in the air.

Some cyanobacteria form harmful algal blooms on coral and reefs and then these toxins affect the things surrounding it. Some can overgrow the host they are living on, and can cause tissue necrosis and mortality if they are harmful. They can also release gas and toxins.