Oxygen and sulfide dynamics in a horizontally migrating cyanobacterial mat: Black band disease of corals

Black band disease is caused by a horizontally migrating microbial consortium which overgrows and kills reef-building corals in many areas of the world. The cyanobacterium Phormidium corallyticum, the sulfide-oxidizing bacterium Beggiatoa sp., fungi, and sulfate-reducing bacteria dominate the consortium, which is generally several mm to 1 cm in width and ca. 1 mm in thickness. Microelectrode measurements revealed photosynthetically produced O2-supersaturation in upper layers during day, although conditions at the band-coral interface were consistently anoxic and, at night, sulfide-rich. Diel distributions of oxygen and sulfide resembled those from cyanobacterial mats in sulfur springs, intertidal mats and hypersaline lagoons.