Chemoautotrophs use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia. Most chemoautotrophs are extremophiles, bacteria or archaea that live in hostile environments (such as deep sea vents) and are the primary producers in such ecosystems.
Autotrophs produce their own energy by one of the following two methods: Photosynthesis - Photoautotrophs use energy from sun to convert water from the soil and carbon dioxide from the air into glucose. Glucose provides energy to plants and is used to make cellulose which is used to build cell walls. E.g.
Plant Autotrophs Plants are all around us. From dandelions to oak trees, we cannot escape the presence of plants. This is a good thing, since not only do they turn carbon dioxide into oxygen, they are a good food source for most of the creatures on earth.