Oceanography Terms

6. The deep ocean layer, where no sunlight reaches
9. Aquatic animals that can swim and move independently of water currents
11. The concentration of salts in water
13. The deepest layer of the ocean, found in ocean trenches
16. Small and microscopic organisms drifting or floating in the sea
17. secreted by corals
18. The rising of cold, nutrient-rich water from deep in the ocean to the surface
19. An opening in the sea floor out of which heated mineral-rich water flows
20. Organisms that live on, in, or near the seabed
21. The extended perimeter of each continent, which lies submerged under relatively shallow seas

1. The layer of the ocean at depths between 4,000 and 6,000 meters
2. An underwater mountain range formed by plate tectonics
3. A deep, narrow depression in the ocean floor, often caused by tectonic activity
4. A flat, almost level area of the deep-ocean basin
5. A layer in a body of water where the temperature changes rapidly with depth
7. The middle layer of the ocean, receiving very little light
8. The steep slope where the continental shelf drops to the deep ocean floor
10. An underwater mountain rising from the ocean floor that does not reach the surface
12. The uppermost layer of the ocean, where sunlight penetrates
14. A diverse underwater ecosystem held together by calcium carbonate
15. A series of ocean waves with extremely long wavelengths caused by large-scale disturbances