Download Earth/Environmental Science Essential Vocabulary Chapter 15 1

Earth/Environmental Science Essential Vocabulary
Chapter 15
1. Salinity- the proportion of dissolved salts to pure water, usually expressed in
parts per thousand (‰)
2. Thermocline- a layer of water in which there is a rapid change in temperature
with depth
3. Density- mass per unit volume of a substance, usually expressed as grams per
cubic centimeter
4. Pycnocline- a layer of water in which there is a rapid change of density with
depth
5. Mixed Zone- an area of the ocean surface with uniform temperatures created
by the mixing of water by waves, currents, and tides
6. Plankton- passively drifting or weakly swimming organisms that cannot move
independently of ocean currents
7. Phytoplankton- algal plankton, which are the most important community of
primary producers in the ocean
8. Zooplankton- animal plankton
9. Nekton- organisms that can move independently of ocean currents by
swimming or other means of propulsion
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Benthos- the forms of marine life that live on or in the ocean bottom
Photic zone- the upper part of the ocean into which sunlight penetrates
Intertidal zone- the area where land and sea meet and overlap
Neritic zone- the marine-life zone that extends from the low-tide line out to
the shelf break
14. Oceanic zone- the marine-life zone beyond the continental shelf
15. Pelagic zone- open ocean of any depth; Animals in this zone swim or float
freely.
16. Benthic zone- the marine-life zone that includes any sea-bottom surface
regardless of its distance from shore
17. abyssal zone- a subdivision of the benthic zone characterized by extremely
high pressures, low temperatures, low oxygen, few nutrients, and no sunlight
18. Primary productivity- the production of organic matter from inorganic
substances through photosynthesis or chemosynthesis
19. Photosynthesis- the process by which plants, algae, and certain
prokaryotes use light energy to convert water and carbon dioxide into energy-rich
glucose molecules
20. Chemosynthesis- the process by which certain microorganisms use
chemical energy to produce food
21. Trophic level- a nourishment level in a food chain
22. Food chain- a succession of organisms through which food energy is
transferred, starting with primary producers
23. Food web- a group of interrelated food chains