Sunlit Zone, Twilight Zone, and Midnight Zone locations in the water column

The ocean’s mesopelagic zone, also known as the ocean twilight zone, is located roughly 100 to 1000 meters below the surface. It begins just beneath the sunlit waters of the upper ocean and ends at the permanently dark waters of the midnight zone. The mesopelagic exists throughout the deep ocean beyond shallow continental shelves and is located mainly on the high seas, but it also extends into the 200-nautical-mile exclusive economic zones (EEZs) of many nations, including those of Small Island Developing States (SIDS) (Illustration by Natalie Renier, © Woods Hole Oceanographic Institution)