gbi12046-sup-0001-FigS1-S7.docxWord document3696K

Fig. S1 (A) Scanning electron micrograph of partially-entombed phosphatized filaments from the Costa Rica margin show a mineral coating (arrow) over the exterior of the organic sheath. (B) Energy dispersive spectroscopy showing typical apatite stoichiometry.

Fig. S2 Light photomicrograph of Thioploca sheath after six weeks of degradation in seawater.

Fig. S3 Internal sulfur globules are a diagnostic feature of sulfide-oxidizing gammaproteobacteria such as Beggiatoa (shown above), as well as Thioploca and Thiomargarita.

Fig. S4 Bundles of Thioploca and individual filaments of Beggiatoa sp. (A) commonly leave behind empty EPS sheath material (B).

Fig. S5 Phosphatic cherts in the Wanjiagou section of the Doushantuo Formation host abundant filamentous structures including both septate and hollow filamentous microfossils that resemble the sheaths and trichomes observed in modern Beggiatoa mats (e.g., Figure S3).

Fig. S6 Electron microprobe profiles across the filamentous Doushantuo microfossils shows in (A) a correlation between carbon (blue) and sulfur (green) specifically confined to the inclusions interpreted as relict sulfur globules. No correlation with iron (yellow) is observed in these inclusions. This signal contrasts sharply with profiles (B) across small pyrite crystals found in the vicinity of the microfossil (Fig. 3), in which sulfur and iron are strongly correlated.

Fig. S7 (A) Partial confocal laser Raman spectrum of kerogen associated with filamentous Doushantuo microfossils showing carbon ‘D’ and ‘G’ bands. The intensity of the G band signal from 1518.9 to 1671.5 cm−1 is mapped in the inset. Scale bar = 6 μm. The D and G bands that are characteristic of the microfossil inclusions are sometimes accompanied by bands in the wave number range from 640 to 740 cm−1 that may indicate carbon-sulfur bonding in the kerogen (B–C). The C-S stretch in modern organic matter is found in this range, but the exact position is dependent on the backbone of the associated carbon (Jenkins et al., 2005).

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