Light micrograph of purple bacteria from a sulfuretum. The bottom of this small water body is permanently anaerobic due to decaying plant inputs, and in this environment there is a community of predominantly anaerobic microorganisms that reduce or oxidize sulfur. Such an ecosystem is called sulfuretum. The picture shows a colony of purple bacteria, probably belonging to the genus Thiocapsa, recognizable by its purple colour. Microscopic contrast method : Differential interference contrast. Magnification 500x at a print width of 10 cm.