Biogeochemical Cycles

Edit Answers
123456789101112131415161718192021222324252627282930313233
Across
  1. 7. phosphorus is most commonly found in nature in the form of these compounds
  2. 9. a type of rock made from shells of marine organisms that contains a lot of carbon
  3. 11. converting atmospheric nitrogen into a form which is usable by plants
  4. 13. as water vapor rises from the surface, it condenses and can form this
  5. 14. chemicals added to soil to improve the productivity of a farm field
  6. 15. changing from liquid to gas
  7. 16. a freshwater source where the groundwater reaches the surface
  8. 18. the slowest of the biogeochemical cycles
  9. 21. the most abundant gas in Earth's atmosphere
  10. 22. a nitrogen-hydrogen compound that can be added to soil as fertilizer
  11. 24. energy is extracted from food using oxygen and producing carbon dioxide
  12. 25. plants and algae use water, carbon dioxide and energy to produce food
  13. 29. the water cycle is also known as the _____ cycle
  14. 31. carbon dioxide produced by animals and released by burning fuels ends up here
  15. 33. much of the nitrogen fixation is done by these organisms
Down
  1. 1. a line which marks the top of a groundwater source (2 words)
  2. 2. the movement of sediment by wind or water
  3. 3. fuels that come from previously living organisms are called ____ fuels
  4. 4. the breaking down of dead organisms that returns substances to the soil
  5. 5. the introduction of harmful materials into the environment
  6. 6. humans artificially increase phosphorus levels in the environment by the use of fertilizers and ____
  7. 8. the release of water vapor from the leaves of plants
  8. 10. a large block of snow and ice that moves slowly downhill
  9. 12. the movement of water through the soil and down into groundwater
  10. 13. water changes from vapor to liquid
  11. 17. water that does not soak into soil and flows downhill
  12. 19. where most of Earth's water is located
  13. 20. water falling to the earth as rain, snow, sleet, etc.
  14. 23. the breaking down of rock by physical and chemical processes
  15. 26. the source of energy that drives the water cycle
  16. 27. water that has filtered through the soil and settled
  17. 28. a solid form of carbon that can be used as a fuel
  18. 30. precipitation falls, water infiltrates soil or flows downhill because of _____
  19. 32. most of Earth's fresh water is in this form