Abyssal Zone

The ocean floor or abyssal zone (1,000-2,000 m (3,281-6,561 ft.)) is dark, chilly, and subject to high pressures. It is located seaward of the continental slope and covers approximately 75% of the ocean bottom. The temperature does not rise above 4 °C. Oxygen allows for a wide ecosystem of invertebrates and fish. Therefore,  some of which have adapted to extreme settings like volcanic vents. Food-producing organisms at this level are chemoautotrophic prokaryotes rather than photosynthetic producers.