Deterioration and microbial colonization of cultural heritage stone buildings in polluted and unpolluted tropical and subtropical climates: A meta-analysis

摘要

Climatic factors, mainly rainfall, temperature and relative humidity, air pollution and biological activity influence the processes of stone degradation. This article analyses results of studies on microbial (mainly cyanobacterial) colonization of 32 cultural heritage stone monuments in Argentina, Belize, Brazil, Cambodia, Laos and Mexico, performed by four of the six authors over several years. Principal components analysis (PCA) and canonical analysis of principal coordinates (CAP) revealed that stone type, calcareous or siliceous, affected cyanobacterial community structure in biofllms. Koppen climate class was important, more temperate climates grouping separately from more tropical sites. Highly polluted cities showed reduced cyanobacterial diversity, with centroid completely separate from the rest; Chroococcus appeared to be relatively pollution-resistant. Buildings at marine sites showed a different and somewhat reduced cyanobacterial diversity. The genus Gloeocapsa was the most frequent genus detected overall, present at all but two sites. Various cases are discussed in more detail, along with the accompanying biodeterioration, and special mention is made of black crusts seen on some buildings. Although some next generation sequencing analyses are discussed, the statistical analyses are based on results of standard microbiological techniques that have been in use for many years and were employed similarly in all the studies.