Premium
Active microbial ecosystem in Iron‐Age tombs of the Etruscan civilization
Author(s) -
Cirigliano Angela,
Mura Francesco,
Cecchini Adele,
Tomassetti Maria Cristina,
Maras Daniele Federico,
Di Paola Monica,
Meriggi Niccolò,
Cavalieri Duccio,
Negri Rodolfo,
Quagliariello Andrea,
Hallsworth John E.,
Rinaldi Teresa
Publication year - 2021
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.15327
Subject(s) - ecosystem , actinobacteria , biology , acidobacteria , proteobacteria , biogeochemical cycle , ecology , microbial mat , cave , ectomycorrhizae , botany , cyanobacteria , symbiosis , bacteria , paleontology , 16s ribosomal rna , mycorrhiza
Summary Earth's microbial biosphere extends down through the crust and much of the subsurface, including those microbial ecosystems located within cave systems. Here, we elucidate the microbial ecosystems within anthropogenic 'caves'; the Iron‐Age, subterranean tombs of central Italy. The interior walls of the rock (calcium‐rich macco ) were painted ~2500 years ago and are covered with CaCO 3 needles (known as moonmilk). The aims of the current study were to: identify biological/geochemical/biophysical determinants of and characterize bacterial communities involved in CaCO 3 precipitation; challenge the maxim that biogenic activity necessarily degrades surfaces; locate the bacterial cells that are the source of the CaCO 3 precipitate; and gain insight into the kinetics of moonmilk formation. We reveal that this environment hosts communities that consist primarily of bacteria that are mesophilic for temperature and xerotolerance (including Actinobacteria, Bacteroidetes and Proteobacteria); is populated by photosynthetic Cyanobacteria exhibiting heterotrophic nutrition ( Calothrix and Chroococcidiopsis ); and has CaCO 3 precipitating on the rock surfaces (confirmation that this process is biogenic) that acts to preserve rather than damage the painted surface. We also identified that some community members are psychrotolerant ( Polaromonas ), acidotolerant or acidophilic (members of the Acidobacteria ), or resistant to ionizing radiation ( Brevundimonas and Truepera ); elucidate the ways in which microbiology impacts mineralogy and vice versa ; and reveal that biogenic formation of moonmilk can occur rapidly, that is, over a period of 10 to 56 years. We discuss the paradox that these ecosystems, that are for the most part in the dark and lack primary production, are apparently highly active, biodiverse and biomass‐rich.