Complex pattern formation of marine gradient bacteria explained by a simple computer model.

We report on the formation of conspicuous patterns by the sulfide-oxidizing bacterium Thiovulum majus and a recently described vibrioid bacterium. These microaerophilic bacteria form mucus veils on top of sulfidic marine sediment exhibiting regular spaced bacterial patterns (honeycombs, interwoven bands, or inverse honeycombs). A simple qualitative computer model, based on chemotaxis towards oxygen and the ability of the bacteria to induce water advection when attached, can explain the formation of the observed patterns. Our study shows that complex bacterial patterns in nature can be explained in terms of chemotaxis and resource optimisation without involvement of cell-cell signalling or social behavior amongst bacteria.