pelagische

Pelagische is a term used in marine biology to describe the open-ocean environment and the organisms that inhabit the water column away from the seabed and shore. It contrasts with demersal habitats, which are near or on the bottom, and with benthic environments that lie on or within the seabed. The pelagic realm encompasses a wide range of life forms, from microscopic phytoplankton to large nekton such as fishes, squids, seals, and whales, as well as the communities that depend on them.

The pelagic zone is commonly divided by depth and light availability. The epipelagic, or sunlit zone, extends from the surface to about 200 meters and supports most photosynthesis. The mesopelagic, or twilight zone, ranges roughly from 200 to 1000 meters and features organisms adapted to low light. Beyond these, the bathypelagic, abyssopelagic, and hadopelagic zones include progressively darker and deeper waters. Many pelagic species undertake diel vertical migrations, ascending at night to feed near the surface and returning to depth by day, a behavior that distributes energy and nutrients through the water column.

Ecology and adaptations in the pelagic environment are diverse. Plankton form the base of pelagic food webs, while nekton such as tuna, mackerel, squid, and various marine mammals move actively through the open ocean. Adaptations include streamlined bodies for efficient swimming, schooling behavior for protection and feeding, and, in deeper regions, bioluminescence and specialized sensory systems.

Human activity affects pelagic ecosystems through fisheries targeting open-water species, pollution, and climate-related changes in temperature, circulation, and nutrient dynamics. Management and research efforts emphasize sustainable harvests, ecosystem-based approaches, and protections for vulnerable deep-pelagic habitats.