The Nitrogen Cycle

1. What is the largest natural reservoir for nitrogen on Earth?
3. Decomposers break down dead organisms and waste, returning nitrogen as ammonia.
4. Bacteria convert nitrates back into N₂ gas, returning it to the atmosphere.
9. fixation, What process turns nitrogen into ammonium?
10. fertilizer (nitrates) runs into water bodies, causing algal blooms and dead zones.
12. Which process in the nitrogen cycle turns dead plants and animals to ammonium?
13. nine, What percentage of air is nitrogen?
15. which process in the nitrogen cycle turns ammonium into nitrates?
16. How do animals obtain nitrogen?
17. What natural event can convert atmospheric nitrogen into a usable form?
18. How do plants obtain nitrogen?

1. fertilizers, The primary cause of excess nitrogen in many ecosystems today
2. What is the atomic number for Nitrogen?
5. What group on the periodic table does nitrogen fall under?
6. fixing bacteria, What is the most common way that nitrogen fixation occurs?
7. Plants absorb nitrates and ammonia through roots, incorporating them into organic matter.
8. Family of plants that have a symbiotic relationship with nitrogen fixing bacteria
11. First step in the process of making nitrogen usable by plants.
14. What percentage of the atmosphere is made up of nitrogen?
15. cycle, Nitrogen being fixed, used by plants, and later returned to the atmosphere