Diversity of Terrestrial Cyanobacteria Colonizing Selected Stone Monuments in Serbia

ABSTRACT

The presence of biofilms on stone monuments can lead to biodeterioration processes that significantly lower not only the aesthetic value of cultural heritage sites but also cause considerable physical and chemical damage to stone surfaces. In terrestrial environments, cyanobacteria have a significant role in biofilm formation on a variety of natural and artificial stone substrata, including granite, sandstone, limestone, lime mortar, etc. Studies on cyanobacterial diversity and estimation of biodeteriorative activity on stone cultural heritage objects can be very important for conservators and restorers, and cyanobacteria removal from stone monuments is currently a great challenge for conservation science. In that sense, the diversity of terrestrial cyanobacteria was investigated at six localities in Serbia. Samples for cyanobacterial analyses were taken from surface biofilms covering different substrata: granite and lime mortar (The Monument to the Unknown Hero), sandstone (Branko's Bridge, Eiffel’s Lock) and carbonate rock (Medieval tombstones from Mramorje and Rastište, Gradac Monastery). A total of 18 cyanobacterial taxa were identified. The highest diversity was found on carbonate rock, followed by sandstone. Cyanobacteria were also recorded on an artificial substratum – lime mortar, while cyanobacteria were not found on granite. All detected cyanobacteria seriously impaired the structural and aesthetic integrity of the studied monuments via mechanical and chemical actions, so their presence must not be overlooked.

KEYWORDS:

• Biodeterioration
• biofilm
• carbonate rock
• cyanobacteria
• DCA
• granite
• mortar
• sandstone

Acknowledgments

The authors would like to thank Dragan Stanojević, Aleksa Jelikić, and Maja Đorđević of Republic Institute for the protection of cultural monuments-Belgrade and Veselin Lađić from Garnet d.o.o. for giving access and permission to investigate the studied sites.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is a part of research realized within the projects No. 176020 and No. 176018 financially supported by the Ministry of Education, Science and Technological Development of Serbia [Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja].