Hydrothermal vents may be several thousand meters deep, making finding new areas of vent activity quite challenging. Chemical signatures from dissolved minerals in sampled vent fluid, as well as temperature and pH changes help scientists to find these elusive regions and their associated chemosynthetic communities. In this investigation, students collect and analyze data as evidence to explore the phenomenon: How do physical and chemical cues help scientists locate hydrothermal vents and other unique deep seafloor habitats?