Microbial biofilm community structure and composition on the lithic substrates of Herculaneum Suburban Baths

• Published in: PloS one Vol. 15; no. 5; p. e0232512
• Main Authors: De Natale, Antonino, Mele, Bruno Hay, Cennamo, Paola, Del Mondo, Angelo, Petraretti, Mariagioia, Pollio, Antonino
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.05.2020; Public Library of Science (PLoS)
• Subjects: Algae; Architecture; Bacteria; Baths; Biofilms; Biology and Life Sciences; Community structure; Composition; Cyanobacteria; Deoxyribonucleic acid; DNA; Ecology and Environmental Sciences; Environmental aspects; Environmental conditions; Environmental quality; Excavations (Archaeology); Fungi; History; Humidity; Irradiation; Italy; Medicine and Health Sciences; Microbial mats; Microbiological research; Microorganisms; Microscopy; Mortars (material); Plasters; Properties; Public baths; Radiation; Rare species; Scanning microscopy; Structure (Literature); Substrates; Suburban areas; Swimming pools; Italy; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0232512

In this work, we want to investigate the impact of different substrates and different environmental condition on the biofilm communities growing on plaster, marble, and mortar substrates inside the Herculaneum Suburban Baths. To do so, we measured environmental conditions and sampled biofilm communities along the walls of the baths and used culture-dependent and -independent molecular techniques (DGGE) to identify the species at each sampling sites. We used the species pool to infer structure and richness of communities within each site in each substrate, and confocal light scanning microscopy to assess the three-dimensional structure of the sampled biofilms. To gather further insights, we built a meta-community network and used its local realizations to analyze co-occurrence patterns of species. We found that light is a limiting factor in the baths environment, that moving along sites equals moving along an irradiation gradient, and that such gradient shapes the community structure, de facto separating a dark community, rich in Bacteria, Fungi and cyanobacteria, from two dim communities, rich in Chlorophyta. Almost all sites are dominated by photoautotrophs, with Fungi and Bacteria relegated to the role of rare species., and structural properties of biofilms are not consistent within the same substrate. We conclude that the Herculaneum suburban baths are an environment-shaped community, where one dark community (plaster) and one dim community (mortar) provides species to a "midway" community (marble).