(klo-row-mace-ee-um) aggregatum. encountered in a habitat with very low levels of oxygen, with many iron bacteria. These motile consortia of green sulphur bacteria (Chlorobium
) are much smaller than most cyanobacteria and without the granular texture often associated with cyanobacteria. There are two clusters of four green bacteria at either end, and a single rod-shaped colourless motile bacterium in the centre of each polar cluster. More details: Croome, R.L. & Tyler, P. A. 1984. J. Gen. Microbiol., 130: 2717-2723). Phase contrast.