Exercise 4 (Moduales 34.6-34.7)

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Across
  1. 2. ___ vents are densely populated communities of the deep sea.
  2. 3. The bottom of the sea, a lake, or a river is called the ____ realm.
  3. 5. ___ Is only possible in the photic zone.
  4. 7. ___ are drifting animals in the pelagic realm.
  5. 10. The ___ shelves are the submerged edges of the continents.
  6. 11. Nitrogen and ___ may be limiting nutrients in lakes and ponds.
  7. 13. Drifting algae and cyanobacteria make up the ___.
  8. 15. The oceans are threatened by their use as a ___ ground for waste.
  9. 17. Light does not reach the ____ zone.
  10. 19. ___ reefs are diverse communities in warm, shallow waters.
  11. 20. Near a river's mouth, the water may be murky with _____.
  12. 22. A ___ is an ecosystem intermediate between aquatic and terrestrial ones.
Down
  1. 1. ___ of an estuary may vary, depending on the mix of salt and fresh water.
  2. 4. Seasonal ___ in a lake brings nutrients to the surface and oxygen to the bottom.
  3. 6. Wetlands include swamps, bogs, and ____.
  4. 8. The ___ zone is the area of near the surface where light can penetrate.
  5. 9. Near a river's source, the water is usually cool and ___.
  6. 12. Motile animals like fishes and whales live in the ___ realm.
  7. 14. Decomposition on a lake bottom may deplete the water of ____.
  8. 16. The ___ zone is flooded by tides every 12 hours.
  9. 18. The availability of ___ has a major effect on organisms in the sea.
  10. 21. An ___ is a coastal area where fresh and salt water meet.