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

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

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

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

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

Additional file 6: Table S6. of Microbial biodiversity assessment of the European Space Agency’s ExoMars 2016 mission

Txt formatted biom table of MiSeq amplicon data. (TXT 102 kb

Additional file 9: Table S8. of Microbial biodiversity assessment of the European Space Agency’s ExoMars 2016 mission

Retrieved microbial isolates, the sampling date, location and enrichment strategy (“Fungi” refers to PD agar, see materials and methods). (XLSX 30 kb