Purple bacteria II

Purple bacteria or purple photosynthetic bacteria are pigmented by bacteriochlorophyll and carotenoids, giving them a colourful range of purples, pinks and oranges. They photosynthesize without producing oxygen as a by-product. This type of bacteria are proteobacteria which are phototrophic (produce their own food via photosynthesis).

One type, purple sulphur bacteria, deposit elemental sulphur –brimstone – instead. Others oxidise iron to form rusty banded iron formations.

Cyanobacteria at work

Also known as blue-green algae, cyanobacteria are arguably the most successful group of microorganisms alive today. They are genetically very diverse, and able to live almost anywhere, even in extreme conditions. The nitrogen-fixing cells are bright little suns here, in a stormy sea.