The most common autotrophic organisms on Earth are photoautotrophs such as plants, eukaryotic algae, and cyanobacteria. It is possible for non-phototrophic microbes to be autotrophic. They use inorganic chemicals for energy and electrons. What descriptive name would these microbes have? Often these microbes are found deep in the ocean in geo-thermal vent regions. What temperature requirements would you suspect they have? Explain. Which cellular structures must be adapted to deal with this extreme environment? How might they be adapted? If these microbes lacked superoxide dismutase, catalase, and peroxidase what can you conclude about the effect of molecular oxygen on their growth? Explain. Since these microbes live in the ocean how would you categorize their salt requirements? Explain how they survive.