These are sequences from the final time point of ~24 h incubations of diffuse-flow hydrothermal vent fluids from "Crab Spa" (9o50.3981 N, 104o17.4942 W). All but two samples were incubated at 24 C, the remaining two were incubated at 50 C. Further details about sampling and experimental conditions are available in an accepted publication by McNichol et al (2016) entitled "Assessing Microbial Processes in Deep-Sea Hydrothermal Systems via Incubations at In Situ Temperature and Pressure" to be published in Deep-Sea Research Part I. A forthcoming publication will also use these data.