Geochemical heterogeneity of sublacustrine hydrothermal vents in Yellowstone Lake, Wyoming

•Sublacustrine vent fluids are not recharged by lake water, implying subsurface thermal flow on the scale of several km.•The formation of distinctive sublacustrine fluids is attributed to similar processes that affect subaerial counterparts.•The lack of atmospheric O2 limits oxidation in sublacustrine vent fluids.•Owing to lake water pressure, vent fluids reveal aspects of deeper geothermal geochemical processes at Yellowstone.