Chemotroph

A chemotroph is an organism that gets its energy by changing certain molecules in its environment. This process is called oxidation. It takes electrons from other molecules. These molecules can be living (chemoorganotrophs) or non-living, like minerals (inorganic; chemolithotrophs). Unlike plants and some bacteria that use sunlight, called phototrophs, chemotrophs use chemical reactions for power.

Chemotrophs can make their own food from simple substances. This makes them autotrophic. Or they might need to take food from other organisms, making them heterotrophic. These organisms often live in special places where the molecules they need are abundant. Examples are around deep-sea hydrothermal vents.

Examples of chemotrophs include certain types of iron-oxidizing bacteria and archaea that produce methane. These tiny creatures play a big role in Earth's ecosystems, especially in extreme environments where sunlight never reaches.

Chemoautotroph

Chemoautotrophs are special organisms that make their own food using energy from chemical reactions instead of sunlight. They take simple, inorganic materials like hydrogen sulfide, sulfur, or iron from their environment and use them to create energy and build organic compounds from carbon dioxide.

Most chemoautotrophs are tiny, single-celled bacteria or archaea that live in extreme places like deep sea vents. They are important because they form the base of the food chain in these harsh ecosystems.

Chemoheterotroph

Chemoheterotrophs are living things that cannot make their own food. They get their energy by breaking down other natural materials such as carbohydrates, lipids, and proteins. Many animals and fungi are chemoheterotrophs.

Some special chemoheterotrophs include iron-oxidizing bacteria. These use iron to get energy. There are also archaea called methanogens that make methane gas. Methanogens live in places like swamps and the guts of some animals. They help break down organic matter. They are important because they make methane, a gas that affects our climate.