The oceanic zone is typically defined as the area of the ocean lying beyond the continental shelf (such as the Neritic zone), but operationally is often referred to as beginning where the water depths drop to below 200 meters (660 feet), seaward from the coast into the open ocean with its Pelagic zone. It is the region of open sea beyond the edge of the continental shelf and includes 65% of the ocean’s completely open water. The oceanic zone has a wide array of undersea terrain, including trenches that are often deeper than Mount Everest is tall, as well as deep-sea volcanoes and ocean basins. While it is often difficult for life to sustain itself in this type of environment, many species have adapted and do thrive in the oceanic zone. There are four ocean zones: the Sunlight zone, the Twilight zone, the Midnight zone, and the Abyssal zone.
