Fig. 1.

Overview of Tramway Ridge, Mt. Erebus. a Tramway Ridge is located near the summit of Mt. Erebus, a volcano on Ross Island, in the Ross Sea region of Antarctica (indicated by green marker on the satellite image). Photos from top to bottom: aerial image of the main crater of Mt. Erebus, which harbours an active lava lake; looking up towards the volcano from the shore of Ross Island; images of Tramway Ridge hot soils, including sampling in Tyvek suits (photos courtesy of Jon Tyler and Stephen Noell). Satellite imagery is from the Antarctic Digital Database Map Viewer https://www.add.scar.org/, Open Source. b Simple cutaway schematic of a fumarole. Water vapour and gasses heated underneath the surface are released at fumaroles, which host diverse and unique microbial lineages. The network on the right is the “intra-correlated groups” (ICGs) of Herbold et al., 2014 [4]. Nodes correspond to OTUs formed from 16S ribosomal RNA gene amplicons. Vertical placement of ICGs indicate an estimate of the location of maximal ICG abundance, based on data in Herbold et al., 2014 [4]. Blue lines indicate a positive correlation between OTUs, with the width of the line corresponding to the strength of the correlation. ICGs are background-shaded with the surface-associated ICG background-shaded in green. OTUs indicated with numbers 1 & 2 represent abundant, potentially endemic organisms discussed at length in this manuscript