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Author(s): Deanne Erdmann MS

Zonation in a Marine Environment

The marine environment is categorized by distance from shore, amount of light, and depth of water. The photic zone (depths which receive sufficient light to support photosynthesis) consists of the intertidal zone (exposed to air when the tide changes), the neritic zone (water less than 300 meters deep) and the oceanic zone. Water depths that receive insufficient light to support photosynthesis are designated as aphotic. The third ocean environment consists of the bottom or benthic zone, which spans across all ocean depths. A variety of organisms that feed on detritus (decomposing organic matter) live in the benthic zone. The deepest benthic area is referred to as the abyssal zone. Organisms living in the abyssal zone (usually considered to be at depths greater than 12,000 ft or 4,000 m) are adapted to extremely cold temperatures and high pressures.