Lang, SQ, Früh-Green, GL, Kelley, DS, Lilley, MD, Proskurowski, G and Reeves, EP (2012) H2/CH4 ratios cannot reliably distinguish abiotic vs. biotic methane in natural hydrothermal systems. Proceedings of the National Academy of Sciences, 109(47). E3210-E3210. doi:10.1073/pnas.1213138109