title: Algal and cyanobacterial biofilms on calcareous historic buildings.
abstract: Major microorganisms in biofilms on external surfaces of historic buildings are algae, cyanobacteria, bacteria, and fungi. Their growth causes discoloration and degradation. We compared the phototrophs on cement-based renderings and limestone substrates at 14 historic locations (47 sites sampled) in Europe and Latin America. Most biofilms contained both cyanobacteria and algae. Single-celled and colonial cyanobacteria frequently constituted the major phototroph biomass on limestone monuments (32 sites sampled). Greater numbers of phototrophs, and especially of algae and of filamentous morphotypes, were found on cement-based renderings (15 sites), probably owing to the porosity and small pore size of the latter substrates, allowing greater entry and retention of water. All phototrophic groups were more frequent on Latin American than on European buildings (20 and 27 sites, respectively), with cyanobacteria and filamentous phototrophs showing the greatest differences. The results confirm the influence of both climate and substrate on phototroph colonization of historic buildings.
authors.affiliation: CPG Agricultural and Environmental Microbiology/Federal University of Rio Grande do Sul (UFRGS), Av. Bento Goncales 9500, Porto Alegre-RS, CEP 91501-970, Brasil.
authors.forename: Cezar A
authors.initials: CA
authors.lastname: Crispim
authors.forename: Peter M
authors.initials: PM
authors.lastname: Gaylarde
authors.forename: Christine C
authors.initials: CC
authors.lastname: Gaylarde
mesh_terms: D001108:Architecture; D018441:Biofilms / Q000254:growth & development*; D018533:Biomass; D002119:Calcium Carbonate; D000458:Cyanobacteria / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification*; D056890:Eukaryota / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification*; D005060:Europe; D007843:Latin America
chemical_list: D002119:Calcium Carbonate