| biogenic black crusts on buildings in unpolluted environments. | samples of peeling black crusts from modern and historic buildings in campeche, mexico, from a gravestone on the island of dom khon, lao, and from the anglican cathedral in belize city were analyzed microbiologically, by scanning electron microscopy plus electron dispersive spectroscopy (eds) and for pigment composition. in all cases, the surface was covered by a thick mat of cyanobacteria with dark brown sheaths. these were filamentous organisms of the genera scytonema or fischerella/mastigocla ... | 2007 | 17211538 |