djuphavet

Djuphavet is the Norwegian term for the deep sea, referring to the portions of the ocean beyond the continental shelf and extending into the deepest basins. Etymology: djup means “deep” and havet means “the sea.” In Norwegian usage, the term is employed in science, literature, and media to denote the dark, high‑pressure, cold environments far below the sunlit layer.

Definition and scope: There is no single universal depth that defines the deep sea; however, the region most often associated with djuphavet begins around the edge of the continental shelf and includes the mesopelagic, bathypelagic, abyssopelagic, and hadal zones. The depth range commonly linked to the deep sea extends roughly from about 200 meters down to the deepest trenches, though definitions vary by discipline.

Environment and life: The deep sea is characterized by perpetual darkness, near‑freezing temperatures, and high hydrostatic pressure. Organisms are adapted to sparse food resources and extreme conditions; many rely on detrital input from above or on chemosynthesis near hydrothermal vents. Biodiversity includes fish, cephalopods, crustaceans, sponges, and microbial communities. Ecosystems such as hydrothermal vent fields and abyssal plains are of particular scientific interest due to their unique adaptations and roles in carbon cycling.

Exploration and impact: Human exploration has progressed from dredging and submersibles to remotely operated and autonomous vehicles, enabling mapping and in situ observations. The deep sea faces threats from climate change, deep‑sea mining, pollution, and fisheries activity in connected surface systems, with potential consequences for global biogeochemical cycles.

See also: deep sea, pelagic zone, hydrothermal vent, hadal zone.