The abyssopelagic zone is typically 9000 meters underwater and is completely aphotic (devoid of light). Sea life that requires no light lives down here, and can usually make its own light through a process known as bioluminescence. The temperatures are frigid except around hydrothermal vents. Autotrophic organisms that dwell around deep-sea vents are found instead of photosynthetic ones, and serve as the base of the local food web. It can also be called the abyssal zone, or an abysm.