Across
- 4. Volcanoes
- 7. Plants draw water from ground
- 11. Contains 68% of the world's freshwater
- 15. CO2 in, oxygen out
- 17. Ocean, plants, atm
- 18. Nitrites converting to nitrates
- 19. Burning fossil fuels to release energy fast
Down
- 1. Convert nitrate to gasesous nitrogen
- 2. Rocks (weathering)
- 3. Dead materials sink to the bottom of the ocean
- 5. Useable form on nitrogen
- 6. Soil bacteria turning waste into ammonia
- 8. Extra nutrients enter aquatic ecosystem
- 9. Removal of nutrients as water passes through soil
- 10. Taking up nutrients by the roots of plants
- 12. Convert N2gas into biological compound
- 13. Oxygen in, CO2 out
- 14. Burning of fossil fuels
- 16. Drives water cycle
- 20. Water sinking into the ground