Degradation of historical stone monuments by microbes is a serious problem globally.  Damage to the limestone walls of the Old Cathedral of Coimbra, Portugal (UNESCO World Heritage Site) is being investigated by characterizing the phototrophic (light-dwelling) communities.

Lateral view of the Chapel of São Nicolau (Old Cathedral of Coimbra) showing the tomb of D. Sesnando.

A crucial step towards the conservation and preservation of the old walls is understanding the diversity and the role of cyanobacteria (blue-green algae), which can alter the stone, leading to the loss of these important cultural heritage materials.

In order to better understand the role of cyanobacteria in modifying stone, we need to identify them and explore their biodeterioration mechanisms. Soares and colleagues isolated an unknown Nostoc-like cyanobacterium from the Cathedral, which they named as the new genus and species Parakomarekiella sesnandensis.

Details of Parakomarekiella sesnandensis

This represents a first step towards the improvement of this monument’s preservation, as it will allow further evaluation of the possible biodeterioration mechanisms.

Description of Parakomarekiella sesnandensis gen. et sp. nov. (Nostocales, Cyanobacteria) isolated from the limestone walls of the Old Cathedral of Coimbra, Portugal (UNESCO World Heritage Site) by Soares, Fabiana; Ramos, Vitor; Trovão, João; M. Cardoso, Susana; Tiago, Igor; Portugal, António. To be published in the European Journal of Phycology.