Microbes around vents
Part of Hall of Planet Earth.

Microbes are at the base of the food chain. Without them, there would be no animals living at hydrothermal vents. The microbes play a unique role by converting the Earth’s chemical energy into food for the rest of the vent community. For example, some microbes use hydrogen sulfide to convert carbon dioxide, oxygen, and water into organic compounds. Many microbial species live within animals, providing them with food. Others live in the rocks. Some scientists speculate that there exists an enormous subsurface microbial communities.
Some microbes living in the rocks are hyperthermophiic, meaning that they live (and thrive) at temperatures above 80 degrees Centigrade.