Microbial Community Characterizing Vermiculations from Karst Caves and Its Role in Their Formation

Abstract

The microbiota associated with vermiculations from karst caves is largely unknown. Vermiculations are enigmatic deposits forming worm-like patterns on cave walls all over the world. They represent a precious focus for geomicrobiological studies aimed at exploring both the microbial life of these ecosystems and the vermiculation genesis. This study comprises the first approach on the microbial communities thriving in Pertosa-Auletta Cave (southern Italy) vermiculations by next-generation sequencing. The most abundant phylum in vermiculations was Proteobacteria, followed by Acidobacteria > Actinobacteria > Nitrospirae > Firmicutes > Planctomycetes > Chloroflexi > Gemmatimonadetes > Bacteroidetes > Latescibacteria. Numerous less-represented taxonomic groups (< 1%), as well as unclassified ones, were also detected. From an ecological point of view, all the groups co-participate in the biogeochemical cycles in these underground environments, mediating oxidation-reduction reactions, promoting host rock dissolution and secondary mineral precipitation, and enriching the matrix in organic matter. Confocal laser scanning microscopy and field emission scanning electron microscopy brought evidence of a strong interaction between the biotic community and the abiotic matrix, supporting the role of microbial communities in the formation process of vermiculations.

Microeukaryotic and Prokaryotic Diversity of Anchialine Caves from Eastern Adriatic Sea Islands

“…These specific inland environments characterized by a salinity-stratified water column and saltwater exchange with the sea, specific physical and chemical parameters, depth, and isolated position represent the appropriate study sites for allopatric speciation processes. The observed microbial biodiversity is comparable with different cave types in other environments [38]. The conducted CIA resulted in a strong statistically significant correlation between microeukaryotic and prokaryotic communities in the different caves (Fig.…”

The diversity of microbes and prediction of their functions in karst caves under the influence of human tourism activities—a case study of Zhijin Cave in Southwest China

“…Those caves, though dark and oligotrophic with constant low temperature and high humidity, which are not conducive to the microbial existence, can still boast luxuriant microbial resources (Zhang et al 2017(Zhang et al , 2018. Microbes in caves are of great variety, and their community structures, including those in a cave wall in Slovenia (Velikonja et al 2014) and a limestone cave wall in Oylat, Turkey (Yasemin 2016); a cave water body in Florida, USA (Moss et al 2011); phototrophic biofilms in bat caves in Spain (Urzì et al 2010), as well as biofilms on the walls of primitive caves in western New Guinea (Turrini et al 2020); and vermicular sediments in pertosa Auletta cave in southern Italy (Addesso et al 2021), are different from each other. Microorganisms in caves can also build a self-sustaining underground cave ecosystem through the primary production of organisms and Responsible Editor: Diane Purchase biogeochemical cycles (Wu et al 2015).…”

Microbial Communities in Vermiculation Deposits from an Alpine Cave

“…Vermiculation deposits are among the most characteristic features of Morgana Cave. Vermiculation patterns developing on wall surfaces have been found in many caves around the world (Hose and Macalady, 2006;Merino et al, 2014;Bojar et al, 2015;Faucher and Lauriol, 2016;D'Angeli et al, 2017D'Angeli et al, , 2019aD'Angeli et al, , 2019bAddesso et al, 2020).…”

“…Generally, they exhibit several kinds of morphologies (i.e. dots, dendritic, hieroglyphic), colors (red, brown, grey or white) and dimensions (De Waele et al, 2014;Addesso et al, 2020). According to Bini et al (1978) vermiculations are mainly composed of clays and are the Opportunities to obtain samples are rare, and the samples are small and hard to collect due to their mineral composition.…”