We contributed to two papers published this week investigating the molecular mechanisms of adaptation to hydrogen sulfide (H2S) rich environments. In our paper published in Comparative Biochemistry and Physiology A, we show heritable differences in gene expression patterns between sulfide adapted and non-adapted populations. Depending on the organ, sulfide-quinone oxidoreductase (SQR), an enzyme critical to sulfide detoxification, is either constitutively or plastically higher expressed in sulfidic populations. The other paper, published in Nature Communications, also indicated that at least some sulfidic P. mexicana populations exhibit an H2S-resistant cytochrome oxidase (COX), one of the primary targets of H2S toxicity.