Gallionellaceae

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

Gallionella (gally-on-elle-a) one of the iron bacteria, the bacteria attach to surfaces and grow producing a mucus sheath which acquires metal salts as it ages. The bacteria live in a fine tube in the centre of the filament. Phase contrast.

Accumulated accretions of iron bacteria found as epibionts on the leaves of the moss Hygrohypnum. Phase contrast.

Gallionella, iron bacterium. The bacterium creates a filament which adheres to surfaces. Many filaments may form aggregates. The mucus secretions become brown, thicker and more brittle with age.

Gallionella, iron bacterium. The bacterium creates a filament which adheres to surfaces. Many filaments may form aggregates. The mucus secretions become brown, thicker and more brittle with age. Growing cells are to the left.

Iron impregnated capsules of Gallionella.

This image is of a thick brittle film of iron bacteria that formed over the surface of some water taken from the margins of the lake. The bacteria produce tubes of extracellular mucoid material that absorbs metal ions and becomes brown as it ages.