Biodiversity of cyanobacteria and green algae on
monuments in the Mediterranean Basin: an overview
Maria Filomena Macedo,1 Ana Ze´ lia Miller,2 Ame´ lia Dionı´sio3 and Cesareo Saiz-Jimenez4
VICARTE, Departamento de Conservac¸a˜o e Restauro, Faculdade de Cieˆ ncias e Tecnologia,
Universidade Nova de Lisboa, Monte da Caparica, 2829-516 Caparica, Portugal.
The presence and deteriorating action of micro-organisms on monuments and stone works of art
have received considerable attention in the last few years. Knowledge of the microbial populations
living on stone materials is the starting point for successful conservation treatment and control.
This paper reviews the literature on cyanobacteria and chlorophyta that cause deterioration of
stone cultural heritage (outdoor monuments and stone works of art) in European countries of the
Mediterranean Basin. Some 45 case studies from 32 scientific papers published between 1976
and 2009 were analysed. Six lithotypes were considered: marble, limestone, travertine, dolomite,
sandstone and granite. A wide range of stone monuments in the Mediterranean Basin support
considerable colonization of cyanobacteria and chlorophyta, showing notable biodiversity. About
172 taxa have been described by different authors, including 37 genera of cyanobacteria and 48
genera of chlorophyta. The most widespread and commonly reported taxa on the stone cultural
heritage in the Mediterranean Basin are, among cyanobacteria, Gloeocapsa, Phormidium and
Chroococcus and, among chlorophyta, Chlorella, Stichococcus and Chlorococcum. The results
suggest that cyanobacteria and chlorophyta colonize a wide variety of substrata and that this is
related primarily to the physical characteristics of the stone surface, microclimate and
environmental conditions and secondarily to the lithotype.