Biogeochemical Cycles

4. the conversion of nitrogen gas into ammonia
5. an overgrowth of producers (usually algae) in water
9. cycle by which nitrogen is converted into multiple chemical forms as it circulates
14. organisms such as bacteria and fungi that break down waste and dead organisms
15. a reservoir of a substance that accepts more of a substance than it releases
16. organisms, including plants and algae, that make their own food
17. bacteria that convert nitrates in soil or water back to nitrogen gas
18. producers pull carbon dioxide out of the environment and combine it with water in the presence of sunlight
19. extremely low levels of oxygen in water
20. organisms, mainly animals, that eat other organisms to obtain nutrients

1. nutrients required in large amounts such as nitrogen, carbon, and phosphorus
2. matter that organisms require for their life processes
3. a process by which organisms use oxygen to release the chemical energy for sugars and release carbon dioxide and water
6. the routes that carbon atoms take through the environment
7. nutrients required in small amounts
8. bacteria that live freely in soil and provide plants nutrients by fixing nitrogen for them
10. cycle that describes the movement of phosphorus, mostly through the lithosphere and oceans
11. the process of converting ammonia into nitrates
12. cycles in which nutrients circulate endlessly
13. matter maybe be transferred from one type to another, but cannot be created or destroyed