Nutrient Cycles

2. Animals eat ____ containing nitrogen
3. Some organisms use nitrogen to make their own ____
4. The equation for photosynthesis
6. Burning these has released more CO2 in the atmosphere today
8. The ocean is the main _______ of CO2 in the atmosphere
10. Deposits of ____ plants and animals contained large amounts of carbon in the past
11. The process animals use to make CO2 out of oxygen
12. Bacteria that breaks down ammonia into the gaseous form of nitrogen
14. Phosphorus is contained mostly in ____ and minerals
16. A natural source for CO2
18. Phosphorus moves between the ____ and plants

1. This effect is caused by too much CO2 in our atmosphere
3. The process plants using CO2 to make sugar and oxygen
5. This happens when there is too much phosphorus in the water
7. Animal waste products help return the ____ for the next generation of phosphorus in the soil
9. A gas that makes up 78% of our atmosphere
10. An essential nutrient for life that is made from phosphorus
13. Bacteria that use nitrogen in our atmosphere and fixes it so other organisms can benefit
15. Animals and plants ______ directly use all nitrogen found in our atmosphere
17. Fossil fuels include ____, coal, and natural gas