Rarefaction analysis of the microbial communities at the different sampling points.

<p>Curves were calculated by MOTHUR with a 3% distance cutoff.</p

Water chemical parameters from representative areas in the cave.

<p>SI_calcite was calculated using the Merlak algorithm [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180700#pone.0180700.ref037" target="_blank">37</a>].</p

Representative sampling sites in the cave.

<p>A) Calcite raft deposit at Chaos (SO1); B) moonmilk deposit at Piredda Hall (SO2 & SO3); C) manganese oxide deposit at Water Tower site (SO6) and D) sampling of a limestone wall at location Shaft (SO4)</p

Impact of human exploration on the microbial diversity in a hypogean system.

<p>The most abundant human associated genera (as previously described by The Human Microbiome Project Consortium) were used for this analysis and include <i>Lactobacillus</i>, <i>Propionibacterium</i>, <i>Streptococcus</i>, <i>Bacteroides</i>, <i>Corynebacterium</i>, <i>Staphylococcus</i>, <i>Moraxella</i>, <i>Haemophilus</i>, <i>Prevotella</i>, and <i>Veillonella</i>.</p

Venn diagram showing the number of core, unique and shared species among the different sampling points.

<p>Due to the presence of human contaminations, SO1 and SO2 have been omitted. SO6 has been omitted due to the almost sole presence of Proteobacteria.</p

Chemical composition (XRF) of the predominant cave sediments.

<p>Chemical composition (XRF) of the predominant cave sediments.</p

Bacterial and archaeal 16S rRNA gene diversity analyses of samples obtained from the Su Bentu Cave in Sardinia.

<p>Bacterial and archaeal 16S rRNA gene diversity analyses of samples obtained from the Su Bentu Cave in Sardinia.</p

Relative class abundance of A) the whole cave and B) separated into the different sampling sites.

<p>Phylogenetic groups accounting for ≤ 5% of all classified sequences are summarized in the artificial group “others” (Part B). Full relative class abundance is given in Supplementary <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0180700#pone.0180700.t003" target="_blank">Table 3</a>.</p

Gene structure of putative <i>phrA</i> gene of <i>R. varieornatus</i>.

<p>(A) Exon-intron structures of <i>phrA</i> in <i>R. varieornatus</i> and <i>D. melanogaster</i>. (B) Amino acid sequence alignment of the <i>phrA</i> genes between <i>R. varieornatus</i> and <i>D. melanogaster</i>.</p

Capability of reproduction after UVC irradiation in <i>Hypsibius dujardini</i> and <i>Ramazzottius varieornatus</i>. n/a means no data available.

<p>Capability of reproduction after UVC irradiation in <i>Hypsibius dujardini</i> and <i>Ramazzottius varieornatus</i>. n/a means no data available.</p