Cross sections through botryoidal Mn oxides and related sporophores.

<p>(A) Optical microphotograph of a vug with cross section through a botryoidal structure. (B) Magnified and focused part of A showing the cross section of the botryoidal Mn oxide with vague layering at the margin and sporophore-like structures on top. Black mineralized feeder veins are seen underneath the botryoidal structure. White arrows show Mn oxides formed underneath the fossilized biofilm. (C) ESEM image of a cross section through a botryoidal structure showing vague layering at the top margin and sporophores formed as separate cells stacked on each other. (D) ESEM image of a cross section through a botryoidal structure and the distribution of sporophores on its top. (E) Detailed ESEM image of D showing sporophores both made up of separate cells and terminal swelling. (F) ESEM image showing sporophores made up of separate cells and with terminal swelling. Legend: sp, sporophore; spc, sporophore with separate cells on top of each other; spts, sporophores with terminal swelling; la, layering; fv, feeder veins.</p

Raman spectrum of the botryoids.

<p>Raman spectrum (black) of the botryoidal structure identified as todorokite after comparison with RRUFF reference spectra of manganese dioxides from Downs (2006).</p

Raman spectrum of the fossilized biofilm.

<p>Raman spectrum (black) of the material that has fossilized the biofilm and hyphae is identified as Fe-rich smectite of the montmorillonite-nontronite series after comparison with RRUFF reference spectra [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0128863#pone.0128863.ref025" target="_blank">25</a>]. The obtained bands are close to those of nontronite (reference spectrum in red), but exhibit small differences in peak positions. The spectrum is complex and an alternative interpretation is that the material is montmorillonite (reference spectrum in blue) and that the spectrum is influenced by the presence of small amounts of FeOOH, probably lepidocrocite (reference spectrum in green).</p

EPR spectra for abiotic Mn oxide.

<p>EPR spectra for abiotic Mn oxide.</p

Fungal mycelium and botryoidal Mn oxides in a vug.

<p>(A) Optical microphotograph of a vug in basalt lined with a fossilized biofilm of montmorillonite from which fungal hyphae protrude to form a mycelium. Black patches are botryoidal Mn oxides. (B) ESEM image of a vug lined with fossilized biofilm from which hyphae protrude forming a mycelium. Closely associated with the mycelium are black patches of botryoidal Mn oxides. (C) ESEM image of botryoidal Mn oxides. Black arrow show the border of the Mn oxide, note the change in grayscale between the Mn oxide and the underlying montmorillonite. (D, E) ESEM images showing botryoids on the basal parts of hyphae (white arrow). Legend: bf, biofilm; my, mycelium; bmo, botryoidal Mn oxide; hy, hyphae.</p

EPR spectra of the todorokite.

<p>EPR spectra of the todorokite.</p

IR spectra of chabazite.

<p>(A) FTIR spectrum of chabazite single crystal showing bands caused by the chabazite structure. Sample thickness is ca 200 μm. The main band centred at 3500 cm^-1 is caused by water molecules (crystal water), whereas the bands around 2100 and 4000 cm^-1 are caused by crystal lattice overtones. Raman spectrum of the same chabazite crystal in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0140106#pone.0140106.g006" target="_blank">Fig 6</a> confirms the absence of hydrocarbons and the presence of molecular water.</p

Microstromatolites.

<p>(A) Tomographic volume rendering of a multiple microstromatolite at the basalt-vesicle interface (SMNH X5333). (B,C) Tomographic slices of the microstromatolite in A at different levels. The internal structure is characterized by parallel layers in a stromatolitic pattern, and brighter bands towards the margins indicating higher densities. Note how the microstromatolite and surrounding basalt are overgrown by the biofilm and how hyphae protrude. (D) ESEM image of a zeolite crystal (SMNH X5334). A large incorporated microstromatolite is marked with an asterisk. (E) Microphotograph of the marked microstromatolite in D showing a cross section of the internal organization with marginal bands. (F) Microphotograph showing the internal structure of another microstromatolite (SMNH X5335) including layering and the dark marginal band that corresponds to the bright marginal band in SRXTM (compare with B and C). (G) ESEM image of a basalt sample with microstromatolites (SMNH X5336). Frame marks position of H. (H) Close-up of G showing the marginal band.</p

Biofilm containing fungal hyphae.

<p>(A) Removed biofilm containing fungal hyphae; note the tissue-like texture with protruding hyphae and white mineral precipitates. (B) Biofilm showing the fashion of fungal hyphae producing the tissue-like texture of the mat. (C) Fragment of meristematic tissue composed of isodiametric and angular cells. (D, E, H) Fragments of melanised monilioid hyphae. (F, G) Hyphae with endoconidia. Bar = 100 μm (A), 200 μm (B), 10 μm (C), 5 μm (D−H).</p

Powder XRD diffractogram of montmorillonite.

<p>Note the change of basal reflection from 13 Å for dry sample (bottom) to 15 Å for moist sample (top), indicating basal swelling typical of montmorillonite. A relative low signal/noise ratio due to the small amount of available sample material.</p