In this lesson students discover the factors that are indicative of chemotrophic nutritional strategies. This NOAA lesson plan is designed to teach students about the factors that are indicative of chemotrophic nutritional strategies. Students will be able to describe at least three chemotrophic symbioses known from deep-sea habitats. They will identify and explain three indicators of chemotropic nutrition. This hands-on activity uses online data resources and includes: focus questions, background information, evaluations and extensions, as well as resources and student handouts.