Algae and cyanobacteria on painted surfaces in Southern Brazil

Abstract

Algae and cyanobacteria disfigure the external surfaces of buildings and may cause their physico-chemical deterioration. Even though the climate in Brazil is humid, there is no published literature on this problem. The objective of this work was to identify the major phototrophs present on Brazilian constructions in residential, urban and rural sites. The algal and cyanobacterial types present on discolored surfaces of painted buildings in nine different municipalities in Brazil, all lying between latitudes 19° South and 30°S outh, were examined. A total of 816 different organisms was detected in 58 sites. Approximately 63% were single-celled or colonial organisms. The cyanobacterial genus, Synechocystis, was the most biodiverse and frequently comprised the major biomass. It was present in 63.4% of sites. Second and third most frequently detected were Oscillatoria and the algal genus, Chlorella, respectively. The latter organism showed the most widespread occurrence (72.4%). Cyanobacteria were the most important colonizers, especially at urban sites, where over 62% of the organisms detected belonged to this class. Filamentous phototrophs were found in smaller numbers than non-filamentous at all locations.

Fungal colonization and succession on newly painted buildings and the effect of biocide

“…The major biomass on building 2 was fungal, and the diversity of phototrophs on this relatively clean building was less than on building 1, except in a surface crack, where it was greater. The majority of the phototrophs detected on both buildings were coccoid, rather than ¢lamentous, agreeing with results previously obtained on painted surfaces in Brazil [1]. After cleaning, almost no phototrophs were detected and no actinomycetes or protozoa were seen, although they were present on the original surfaces.…”

“…Carpet samples were cultured onto Sabouraud dextrose agar and fungi identi¢ed by cell and colony morphology [11,12]. Tape strip samples taken for phycological analysis were incubated on solid modi¢ed Knop's medium (MKM) and phototrophs identi¢ed as described in Gaylarde and Gaylarde [1] after up to 3 months incubation. The latter sampling and culture technique was also used, with up to 2 weeks incubation, to identify and count fungi directly on the plate by transmitted light microscopy with objectives up to U25.…”

Characterization of fungi transferred by dust storms in Kuwait and their plant pathogenicity

“…This observation is in agreement with the findings of Abdel-Hafez and Shoreit (1985). The mineral-based BG-11 medium was previously reported to be suitable for growth of fungi of different origins (Gaylarde and Gaylarde 1999).…”

Biodeterioration of Mayan buildings at uxmal and tulum, Mexico

“…Most coccoid cyanobacteria cannot be cultured except in mixed cultures which retain the initial spatial relationships of the organisms in the samples. Isolation of pure cyanobacteria in culture prior to identification frequently leads to the loss of coccoid forms and a major diminution in their detection rate (Gaylarde & Gaylarde, 1999). It is also noted that filamentous organisms of the Nostocaceae, Trentepohliaceae and Eustigmatos are frequently present in the biofilms of xerotic surfaces in a coccoid growth form and that Oscillatoriales seldom form long filaments in dry habitats.…”