Oceanography

3. Vent , An opening in the sea floor out of which heated mineral-rich water flows.
4. Plain , A flat, almost level area of the deep-ocean basin.
7. Zone , The deep ocean layer, where no sunlight reaches.
12. Slope , The steep slope where the continental shelf drops to the deep ocean floor.
14. Reef , A diverse underwater ecosystem held together by calcium carbonate structures secreted by corals.
17. Zone , The uppermost layer of the ocean, where sunlight penetrates.
18. , A layer in a body of water where the temperature changes rapidly with depth.
19. , A deep, narrow depression in the ocean floor, often caused by tectonic activity.
20. , An underwater mountain rising from the ocean floor that does not reach the surface.

1. Zone , The deepest layer of the ocean, found in ocean trenches.
2. , The rising of cold, nutrient-rich water from deep in the ocean to the surface.
5. Zone , The layer of the ocean at depths between 4,000 and 6,000 meters.
6. , Aquatic animals that can swim and move independently of water currents
8. , The concentration of salts in water.
9. , Small and microscopic organisms drifting or floating in the sea.
10. , A series of ocean waves with extremely long wavelengths caused by large-scale disturbances.
11. Zone , The middle layer of the ocean, receiving very little light.
13. Shelf , The extended perimeter of each continent, which lies submerged under relatively shallow seas.
15. Ridge , An underwater mountain range formed by plate tectonics.
16. , Organisms that live on, in, or near the seabed.