Betaproteobacteria

Fe-oxidizing microbial matsFe-oxidizing microbial mats. A. Atypical freshwater iron mat in a slow-moving stream where Fe(II)-enriched groundwater is mixing with oxygenated surface water, resulting in growth of Fe-oxidizing bacteria and precipitation of iron oxides; B & C. phase contrast and epiflouresence images of the common sheath-forming Fe-oxidizer Leptothrix ochracea (bar = 5 µm); D, the stalk-forming Fe-oxidizer Gallionella ferruginea, note the bean-shaped cells in the process of cell division at the end of the Fe-oxide encrusted stalk (bar = 5 µm); E, an iron mat associated with a deep-sea hydrothermal vent (1000 mbsl) at Loihi Seamount; F, TEM image of biogenic oxides produced at Loihi, note the variety of helical stalks and tubular sheath-like filaments (bar = 10 µm); G, phase contrast image of unidentified Zetaproteobacteria that are marine Fe-oxidizers growing at the ends of iron-oxide filaments (cells denoted by arrows) from an in-situ incubation at Loihi (bar = 5 µm). Photo credits. A, B, C, D, G – David Emerson; E, Wood’s Hole Oceanographic Institution; F, Clara Chan