24HRAS9

6. Form of oxygen with three atoms in a molecule.
9. Deep pelagic ocean layer between 4,000 to 6,000 meters; cold, dark water.
10. Chemicals controlling plant growth.
11. Forest layer formed by trees' leaves and branches.
15. Fur, hair, or wool coat on mammals.
16. Chemical build-up in a plant or animal, e.g., DDT in bluebirds.
17. Agent to control undesirable organisms; can contaminate water, air, soil, or accumulate in organisms.
19. Water pollution entering from runoff without a specific origin.
22. Chemical transfer from lower to higher trophic levels in a food web or chain.
23. Area of trees and shrubs next to streams, lakes, ponds, and wetlands; helps with erosion and pollution control.

1. Colorless insecticide banned in the U.S. since 1972; caused thinning of raptor eggshells.
2. Earth-supplied raw materials like nutrients, minerals, water, plants, and animals.
3. Production of aquatic organisms under controlled conditions, like fish farming.
4. Organism reflecting a specific environmental condition by its presence, absence, or abundance.
5. Harvesting method removing all trees in an area, followed by replanting or regeneration.
7. Sediment and porous space beneath a stream bed mixing shallow groundwater and surface water; aids aquatic life during droughts.
8. Twilight ocean layer (200 - 1,000m deep) with decreasing sunlight; no photosynthesis.
12. Release of eggs into water by female fish for fertilization by males.
13. On or near water banks; land and plants influenced by adjacent water.
14. Ripened ovary of a seed-bearing plant with accessory parts.
18. Pollution from a specific place like a drain or pipe.
20. Condition of being removed from existence.
21. Relating to or living in deep, open water.