| A | B |
|---|
| abyssal plain | the flat seafloor in the deep ocean. |
| barrier islands | a sand deposit that paralles the shore but is separated from the mainland by water. |
| beach | a deposit of sediment that runs parallel to a seashore. |
| benthos | animals that live on the ocean bottom, such as corals, snails, clams, sea urchins, and bottom-dwelling fish. |
| chemosynthesis | a process used by bacteria to produce food and oxygen by using dissolved sulfur compounds. |
| continental slope | a part of the continental shelf that dips steeply down to the seafloor. |
| continental shelf | The part of every continent that extends out under the ocean. |
| longshore current | an ocean current that runs parallel to the shore, caused by waves hitting the shore at a slight angle. |
| mid-ocean ridge | an underwater mountain range that extends through the middle of most oceans, formed when forces within Earth spread the seafloor apart. |
| nekton | sea-dwelling animals that swim, such as fish, turtles, whales, and seals. |
| ocean trench | a deep trench in the ocean, caused when one piece of seafloor is pushed beneath continental crust. |
| photosynthesis | the process that plants use to make food, using light energy, carbon dioxide, and water. |
| plankton | plants and animals that drift in seawater; most are microscopic. |
| pollution | the addition of harmful substances to an environment. |
| reef | in the ocean, a large underwater colony of coral animals that have become cemented together |
| respiration | the process used by all organisms to combine oxygen with food so that the energy in food can be used. |
| rift zone | an area in the middle of some oceans that contains a system of cracks where the seafloor is rifting, or spreading apart. |
| thermal pollution | the addition of heat to a lake, stream, or ocean by power plants and other industries, which kills organisms that cannot quickly adapt to the warmer water |
| fracture zone | long, narrow ridges or depressions that separate areas of different depths |
| seamounts | underwater mountains often in the form of isolated cones. |
