Chemotroph

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

Chemotrophs can make their own food from simple substances, which 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, such as 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. Some examples include Sulfolobus and Hydrogenovibrio crunogenus, which can grow very quickly.

Chemoheterotroph

Chemoheterotrophs are organisms that cannot make their own food. Instead, they get energy by breaking down other organic materials like carbohydrates, lipids, and proteins. Many animals and fungi are chemoheterotrophs.

Some special types of chemoheterotrophs include iron-oxidizing bacteria, which use iron to get energy, and methanogens, which are archaea that produce methane gas. Methanogens live in many places, such as swamps and the guts of some animals, and help break down organic matter. They are important in nature because they produce methane, a gas that affects our climate.