Beggiatoa (beg-ee-a-toe-a) is a colourless sulphur bacterium which occurs as filaments of various widths. Beggiatoa is found in sediments above the reduced zone. It oxidizes hydrogen sulphide, producing elemental sulphur which is deposited within the bacterial cell as sulphur granules visible inside this filament . May be very long. These cells can glide, a good trait for organisms which live in a habitat the characteristics of which are changing depending on whether there is or is not overlying water or if or if not there is sunlight. They don t usually make these cute spirals. Differential interference contrast.