Pelagic zone

The pelagic zone is the open-water region of a body of water, away from shore and the seafloor. It encompasses the water column from the surface to the greatest depths.

Water column: The vertical body of water extending from the surface to the bottom. The pelagic zone is the portion of this vertical body that lies away from shore and seafloor.
Ocean circulation: The large-scale movement of seawater driven by wind, density differences, tides, and Earth's rotation. Circulation redistributes heat, nutrients, and organisms throughout the pelagic zone.
Pelagic fishery: A fishery that targets species living in the open water rather than near the seabed. Many commercially important fisheries depend on populations inhabiting the pelagic zone.
Benthic zone: The ecological region at the bottom of a body of water, including its surface and subsurface sediments. It contrasts with the open-water habitat that defines the pelagic zone.
Photic zone: The sunlit upper layer of water where light supports photosynthesis. This upper pelagic layer supplies the light needed by most marine photosynthesis.
Upwelling: The rise of deep, nutrient-rich water toward the ocean surface. Upwelling replenishes surface waters and often supports high pelagic productivity.
Highly migratory species: Marine animals that travel long distances across national waters and the high seas. Their movements across pelagic habitats make management difficult across borders.
Demersal fish: Fish that live and feed on or near the seafloor. Their close association with the bottom distinguishes them from pelagic fishes.
Aphotic zone: The water layer below effective sunlight penetration, where photosynthesis cannot occur. Much of the deep pelagic zone remains dark and depends on food arriving from above.
Biological pump: The movement of carbon from surface waters into the deep ocean through biological processes. Pelagic organisms drive carbon downward when particles and migrating animals carry it to depth.

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