Light micrograph of purple bacteria and filamentous cyanobacteria 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. In the picture colonies of various purple bacteria, probably belonging to the genus Thiocapsa, can be seen, recognizable by their purple color. Microscopic contrast method : Differential interference contrast. Magnification 220x at a print width of 10 cm.