| A | B |
|---|
| salinity | a measure of the amount of dissolved solids in a given amount of liquid |
| thermocline | a layer of ocean water extending from 300 m below sea level to about 700 m below sea level in which water temperature drops with increased depth faster than in other layers of the ocean |
| water cycle | the continuous movement of water |
| continental shelf | the flattest part of the continental margin |
| continental slope | the steepest part of the continental margin |
| continental rise | the base of the continental slope |
| abyssal plain | the broad, flat portion of the deep-ocean basin |
| mid-ocean ridge | long mountain chain that forms on the ocean floor where tectonic plates pull apart |
| rift valley | a valley that forms in a rift zone between diverging tectonic plates |
| seamount | an individual mountain of volcanic material on the abyssal plain |
| ocean trench | a seemingly bottomless crevice in the deep ocean basin |
| plankton | microscopic organisms that float at or near the ocean's surface |
| nekton | free-swimming organisms of the ocean |
| benthos | organisms that live on or in the ocean floor |
| benthic environment | the ocean floor and all the organisms that live on or in it |
| pelagic environment | the entire volume of water in the ocean and the marine organisms that live above the ocean floor |
| desalination | the process of evaporating sea water so that the water and salt separate |
| nonpoint-source pollution | pollution that comes from many sources and that cannot be traced to specific sites |
