Most autotrophs make food by photosynthesis, but this isn’t the only way that autotrophs produce food. Some bacteria make food by another process, which uses chemical energy instead of light energy. This process is called chemosynthesis. Some chemosynthetic bacteria live around deep-ocean vents known as “black smokers.” Compounds such as hydrogen sulfide, which flow out of the vents from Earth’s interior, are used by the bacteria for energy to make food. Consumers that depend on these bacteria to produce food for them include giant tubeworms, like these pictured in Figure below. Why do bacteria that live deep below the ocean’s surface rely on chemical compounds instead of sunlight for energy to make food?
Tubeworms deep in the Gulf of Mexico get their energy from chemosynthetic bacteria. The bacteria actually live inside the worms.
- Some bacterial autotrophs make food using chemosynthesis. This process uses chemical energy instead of light energy to produce food.