Table 1.

Site names, abbreviations, and minimal set of environmental metadata necessary to separate different microbial community types (temperature, pH, dissolved sulfide or the presence of elemental S; Figure 3).

The three major habitat types sampled include phototrophic mats (green), filamentous “streamer” communities (blue), and archaeal-dominated, elemental sulfur-rich or Fe-oxide sediments (yellow and red, respectively).

¹Physical context refers to location of sample: Examples include: dissected sub-surface layer (under-mat) within a phototrophic mat; high-velocity channels containing filamentous “streamer” communities or down-gradient Fe-oxide mats; S-rich sediment in various geothermal pools

²Target phylum as discussed in submitted “RI-Files” and based on prior molecular, culture, microscopic and/or other investigations performed by individual investigators included in this project (Table S1 in Supplementary Material).

³The sample from Obsidian Pool Prime (OPP_17) represents a different habitat type and was obtained from a large thermal pool after colonization of a glass plate. Physicochemical characteristics place this sample closest to “phototrophic mats” in the current study.