They are photolithotrophic oxidizers of sulfur and most notably utilise a noncyclic electron transport chain to reduce NAD+.

This species looks like a bundle of green bacteria, attached to a central rod-like cell which can move around with a flagellum.

[2] Chlorobium species are thought to have played an important part in mass extinction events on Earth.

They would produce huge quantities of methane and hydrogen sulfide which would cause global warming and acid rain.

Evidence for abundant Chlorobium populations is provided by chemical fossils found in sediments deposited at the Cretaceous mass extinction.

Through the use of comparative genomic analysis, 3 proteins have been identified which are uniquely shared by virtually all members of the Bacteroidota and Chlorobiota phyla.

All of these results provide compelling evidence that the species from these three phyla shared a common ancestor exclusive of all other bacteria and it has been proposed that they should all recognized as part of a single “FCB”superphylum.