The biodiversity of subaerophytic phototrophic biofilms from Maltese hypogea.

Research reveals that subaerial phototrophic biofilms in Maltese hypogea, particularly within the Ħal Saflieni Hypogeum and other catacombs, are dominated by non-heterocytous (Oscillatorialean) cyanobacteria. These microorganisms exhibit cytomorphological and genetic similarities to those found in Mediterranean caves and catacombs, suggesting a widespread distribution of related biofilm communities in such environments. The study employed advanced microscopy techniques, including light microscopy, epifluorescent microscopy, confocal laser scanning microscopy (CLSM), and transmission electron microscopy (TEM), alongside 16S rRNA gene sequencing to isolate and characterize cyanobacterial, microalgal, and chemoorganotrophic bacterial strains. Phylogenetic analyses further confirmed the relatedness of these microorganisms to those in other Mediterranean lithic surfaces.

Zammit, G., Billi, D., Shubert, E., Kaštovský, J., & Albertano, P. (2011). The biodiversity of subaerophytic phototrophic biofilms from Maltese hypogea. Fottea, 11(1), 187–201. https://doi.org/10.5507/fot.2011.018