Which oceanic zone has highest biodiversity?
The epipelagic zone, extending from the surface to roughly 200 metres, generally supports the greatest biodiversity among the listed open-ocean depth zones because it receives enough light for photosynthesis. Phytoplankton convert solar energy and inorganic nutrients into organic matter, forming the energetic base for zooplankton, fishes, turtles, marine mammals, and numerous predators. Warm temperatures, relatively high oxygen, wave-driven mixing, and habitat variation near fronts and floating structures further expand ecological opportunities. Much of the ocean’s primary production occurs he
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 2-3