Chemosynthesis often does produce pure sulfur as a byproduct but so do volcanoes. a priori I'd put the most likely scenario for Mars at chemosynthetic life wit

Chemosynthesis often does produce pure sulfur as a byproduct but so do volcanoes. a priori I'd put the most likely scenario for Mars at chemosynthetic life with photosynthesis never evolving, but this press release doesn't really move the dial on that with the information so far.