| A | B |
|---|
| sonar | a system that uses sound waves to calculate the distance to an object |
| continental shelf | a gentle sloping, shallow area of the ocean floor that extends outward from the edge of a continent |
| continental slope | a steep incline of the ocean floor leading down from the edge of the continental shelf |
| abyssal plain | a smooth nearly flat region of the deep ocean |
| mid-ocean ridge | a continuous range of mountains on the seafloor that winds around the earth |
| trench | a deep sided canyon often found where two plates collide |
| plate | one of the large pieces of the earth's crust |
| seafloor spreading | a process by which new rock is added to the ocean floor along the boundary between two plates moving away from each other |
| intertidal zone | an area that stretches from the highest high-tide on land out to the point on the continental shelf exposed by the lowest low-tide |
| nertic zone | the area of the ocean that extends from the low-tide line out to the edge of the continental shelf |
| open-ocean zone | the ocean beyond the contiental shelf |
| plankton | tiny algae and animals that float in water and are moved by tides and currents |
| nekton | free swimming animals that can move throughout the water column |
| benthos | organisms that live on the bottom of the ocean or other body of water |
| food web | the feeding relationships in a habitat |
| salinity | the amount of salt dissolved in water |
| density | the amount of mass in a given volume |
| water pressure | the force exerted by the weight of water |
| buoyancy | any object, wholly or partly immersed in a fluid, is bouyed up by a force equal to the weight of the fluid displaced by the object |
| sodium chloride | most common salt found in the ocean |
