Freshwater Life Zones

8. at the bottom of the lake.
11. of the shallow sunlit waters near the shore to the depth at which rooted plants stop growing.
15. streams that join into wider and deeper rivers that meander across broad, flat valleys.
18. a newly formed lake that generally has a small supply of plant nutrients.
21. few trees.
22. dominated by trees and shrubs.
23. precipitation that does not sink into the ground or evaporate.

1. receive excess water during heavy rains and floods.
2. a lower layer of colder, denser water, usually with a lower concentration of dissolved oxygen because it is not exposed to the atmosphere.
3. the open, sunlit water surface layer away from the shore that extends to the depth penetrated by sunlight.
4. where the water temperature changes rapidly with depth and with moderate levels of dissolved oxygen.
5. are lands covered with fresh water all or part of time.
6. an upper layer of warm water with high levels of dissolved oxygen.
7. many lakes that fall somewhere between the two extremes of nutrient enrichment.
9. the deep, open water where it is too dark for photosynthesis.
10. aquatic systems where water with a dissolved salt concentration of less than 1% by volume accumulates on or flows through the surfaces of terrestrial biomes.
12. a lake with a large or excessive supply of nutrients needed by producers.
13. headwater or mountain highland streams of cold, clear water rush over waterfalls and rapids.
14. the headwater streams that merge to form wider, deeper streams that flow down gentler slopes with fewer obstacles.
16. have waterlogged soils, which tend to accumulate peat, and may or may not have trees.
17. the land area that delivers runoff, sediment, and dissolved substances to a stream.
19. precipitation that flows into streams.
20. are depressions carvd out by glaciers.