The marine benthic zone consists of the seafloor below the surface waters of the coastal, or nertic, zone and the offshore, pelagic zone Except for shallow, near-coastal areas, the marine
benthic zone receives no sunlight. Water temperature declines with depth, while pressure increases. As a result, organisms in the very deep benthic, or abyssal, zone are adapted to continuous cold (about 3°C) and very high water pressure.
Except in areas of organic enrichment, oxygen is usually present at sufficient concentrations to support diverse animal life.