CHAPTER 20

5. the movement of deep, cold ,and nutrient rich water to the surface
6. Zone: confined to the ocean trenches, which are deeper than 6,000m below the surface of the water
7. ocean water is heated to remove salt
8. the mass of mostly microscopic organisms that float freely in the waters of aquatic (freshwater and marine)environments
9. Zone: the bottom region of oceans and bodies of fresh water
11. are microscopic plants in the ocean that provide food for many of the oceans organisms
14. Osmosis Desalination: a popular method for desalinating ocean water
15. Zone: has no sunlight because it begins at a depth of 4,000m and extends to a depth of 6,000m
17. Zone: the shallowest benthic zone lies between the low tide and high tide lines
19. all organisms that swim actively in open water, independent of currents

1. a layer in a body of water in which water temperature drops with increased depth faster than it does on other layers
2. a measure of the amount of dissolved salts in a given amount of liquid
3. Zone: the region of an ocean or body of fresh water above the benthic zone
4. a process of removing salt from ocean water
9. organisms that live at the bottom of oceans or bodies of fresh water
10. elements: elements that exist in very small amounts
11. Ice: a floating layer of sea ice that completely covers an area of the ocean surface
12. the raising of aquatic plants and animals for human use or consumption
13. when water freezes, the first ice crystals that form do not contain salt. The ice can be removed and melted to obtain fresh water
16. Zone: extends onto the deep waters beyond the continental shelf
18. the mass of a substance per unit volume is that substances