The marine benthic zone consists of the seafloor below the surface waters of the coastal, or neritic,
zone and the offshore, pelagic zone.
The very deep benthic, or abyssal, zone are adapted to continuous cold and extreme pressures.
Around deep-sea hydrothermal vents, which are sites of volcanic activity on mid-ocean ridges, the producers are chemoautotrophic prokaryotes that obtain energy by oxidizing H2S formed by a reaction of hot water with dissolved sulfate (SO42-).
A diverse community of exotic organisms live in this lightless world.