1. Biogeochemical Cycles
Enviro 2 Go , ,

2. Biogeochemical Cycles
Objectives- You should be able to:
Explain how certain biogeochemical cycles work.
Identify how humans are impacting the biogeochemical cycles.
Recognize the parts of each cycle.

3. Biogeochemical Cycles
A BIOGEOCHEMICAL CYCLE is a circuit, or pathway, by which an element or molecule moves through both biotic and abiotic components of an ecosystem.
We will study the following biogeochemical cycles:
Water
Carbon
Nitrogen
Phosphorus

4. Water Cycle Water is the basic building block of ALL life on Earth.
Water regulates the temperature of the planet and cycles essential nutrients through the biosphere and all living things.
The flow of water through the biosphere is called the water cycle.

5. Water Cycle Important Vocabulary: Condensation Precipitation
Evaporation
Transpiration

6. Condensation
The transformation of water vapor to liquid water droplets in the air, producing clouds and fog is known as condensation.

7. Precipitation
Condensed water vapor that falls to the Earth's surface is precipitation. Most precipitation occurs as rain, but also includes snow, hail, and sleet.

8. Evaporation
Evaporation is the process by which liquid water is heated by the sun and rises into the atmosphere as water vapor.

9. Transpiration
Transpiration is the evaporation of water from the leaves of plants.

10. REMEMBER THIS!!!
Water enters the atmosphere through evaporation and transpiration.
Transpiration is the evaporation of water from plants.
Water returns to the earth through precipitation.

11. Interesting Scientific Fact
Changing the solid form of water (ice) to the liquid state of water requires heat. Changing water back into ice gives off heat. Knowing this, orange farmers in southern states spray their orange trees with water to prevent them from freezing during sudden cold snaps. The way it works is simple. As the water begins to freeze on the orange trees, it gives off heat which then prevents the fruit from freezing. The crop is saved.

12. Water Cycle Summary
Now that you have learned about the water cycle, check out the:
Water Cycle Animation

13. Questions??? Question 1: How does water return to the earth?
Question 2: What is transpiration?
Question 3: How does water enter the earth’s atmosphere?

14. Carbon Cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the biosphere and living organisms.
Carbon is an essential component of proteins, fats and carbohydrates which make up all LIVING ORGANISMS.

15. Carbon Cycle Important Vocabulary Cellular Respiration Photosynthesis
Decomposition
Combustion
Fossil Fuels
Coal
Oil
Natural Gas

16. Carbon Cycle
Carbon exists in the Earth's atmosphere primarily as the gas carbon dioxide (CO2).
Carbon is taken from the atmosphere and returned to the Earth by the process of PHOTOSYNTHESIS.
Carbon can be released back into the atmosphere in many different ways, including:
Cellular Respiration
Decomposition
Combustion

17. Photosynthesis Remember Photosynthesis?
Plants take carbon dioxide from the atmosphere, combine it with light energy and water to produce glucose and oxygen.
CO2 + H2O + light energy → C6H12O6 + O2
(carbon dioxide) + (water) + light energy → (glucose) + (oxygen)

18. (glucose) + (oxygen) → (carbon dioxide) + (water)
Cellular Respiration
Remember Cellular Respiration?
Cellular Respiration, performed by BOTH plants and animals, involves the breaking down of glucose into carbon dioxide and water.
C6H12O6 + O2 → CO2 + H2O
(glucose) + (oxygen) → (carbon dioxide) + (water)
The Carbon Dioxide is then released back into the atmosphere.

19. Decomposition
Carbon is returned to the earth and released into the atmosphere through the decay of plants and animals.
Decomposers, such as fungi and bacteria, break down the carbon compounds in dead animals and plants and convert the carbon into carbon dioxide in the presence of oxygen, or methane if oxygen is not present.

20. Combustion
Combustion is the burning of fossil fuels such as coal, oil, and natural gas. Combustion releases carbon that has been stored in the Earth’s crust for millions of years into the atmosphere as carbon dioxide.

21. Interesting Scientific Fact:
When some prehistoric plants and animals died, they became buried over time by layers of Earth. During that time, they were changed into fossil fuels such as coal, oil, and natural gas. The carbon contained in those once living organisms is burned as a fuel for cars. That same carbon is then released into the atmosphere.

22. Humans Affects on the Carbon Cycle
Combustion (burning fossil fuels)
Driving their cars A LOT!
Deforestation (destroying vegetation that absorbs carbon dioxide)

23. REMEMBER THIS!!!
Carbon enters the atmosphere through cellular respiration, decomposition, and combustion.
Carbon is absorbed from the atmosphere through photosynthesis.
Humans have GREATLY impacted the carbon cycle by putting more carbon dioxide into the atmosphere through combustion than what is removed by photosynthesis!

24. Carbon Cycle Animation
Carbon Cycle Summary
Now you have learned about the carbon cycle, check out the:
Carbon Cycle Animation

25. Questions??? Question 4: How does carbon enter the atmosphere?
Question 5: How is carbon removed from the atmosphere?
Question 6: How does carbon enter living organisms?
Question 7: How are humans impacting the carbon cycle and what is one of the results from human impact?

26. Nitrogen Cycle
The nitrogen cycle is the biogeochemical cycle by which nitrogen is exchanged between the biosphere and living organisms.
The Earth's atmosphere is about 78% nitrogen; however, it is in the form of nitrogen gas and is unusable by most living organisms.
Nitrogen is essential for many biological processes; and is crucial for any life here on Earth.
Nitrogen helps build our proteins!

27. Nitrogen Cycle Important Vocabulary Legumes Root Nodules
Nitrogen-Fixing Bacteria

28. Nitrogen Cycle
Nitrogen in the atmosphere is unusable to plants and animals.
In order for nitrogen gas to be usable, it needs to be “FIXED.”
Nitrogen-fixing bacteria create usable forms.
Lightning also “fixes” atmospheric nitrogen.

29. Nitrogen-Fixing Bacteria
Without Nitrogen-fixing bacteria, there would not be enough usable nitrogen available to living organisms.
Nitrogen-fixing bacteria “fix,” or change the nitrogen gas from the atmosphere into a usable form for living organisms.

30. Nitrogen-Fixing Bacteria
Nitrogen-fixing bacteria live on the root nodules of legumes.
Legume plants include: beans, peas, and clover
The legumes provide habitat for the bacteria while the bacteria provide nitrogen to the plant.

31. Human Impacts on the Nitrogen Cycle
Increased global concentrations of nitrous oxide (N2O) creates acid rain.
Increased use of fertilizers increases nitrogen runoff into our waterways and contributes to eutrophication.

32. REMEMBER THIS!!!
Atmospheric nitrogen (gas) is unusable by most living organisms.
Nitrogen-fixing bacteria provide most of the usable nitrogen.
Nitrogen-fixing bacteria are found on the root nodules of legumes.

33. Nitrogen Cycle Summary
Now you have learned about the nitrogen cycle, check out the:
Nitrogen Cycle Animation

34. Questions??? Question 8: Where is most nitrogen found?
Question 9: Where does usable nitrogen come from?
Question 10: What type of relationship exists between nitrogen-fixing bacteria and legumes?

35. Phosphorus Cycle
The phosphorus cycle may also be referred to as the mineral cycle.
The phosphorus cycle is the movement of phosphorus from the environment to organisms and then back to the environment.
Phosphorus is mainly found in water, soil, and rock.
Phosphorus is essential for life.
Component of DNA
Building block of our bones and teeth.

36. Phosphorus Cycle

37. Phosphorus Cycle
Unlike the other cycles, phosphorus cannot be found in air in the gaseous state.
The phosphorus cycle is the SLOWEST cycle.
Phosphorus is most commonly found in rock formations and ocean sediments as phosphate salts.
Phosphate salts that are released from rocks through weathering usually dissolve in soil water and will be absorbed by plants.

38. Phosphorus Cycle
Animals absorb phosphates by eating plants or plant-eating animals.
When animals and plants die, phosphates will return to the soils or oceans again during decomposition.
After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years. Eventually, phosphorus is released again through weathering and the cycle starts over.

39. Human Impacts on the Phosphorus Cycle
Like nitrogen, increased use of fertilizers increases phosphorus runoff into our waterways and contributes to eutrophication.

40. REMEMBER THIS!!! Most phosphorus is found in rocks and soil.
The phosphorus cycle is the slowest cycle.
Excess phosphorus contributes to eutrophication.

41. Phosphorus Cycle Summary
Now you have learned about the phosphorus cycle, check it out on the:
Phosphorus Cycle Animation

42. Questions??? Question 11: Where is most phosphorus found?
Questions 12: What is phosphorus used for in humans?

43. Test Yourself True or False
___ 1. Water that changes from a gas to a liquid is evaporating.
___ 2. Water that changes from a gas to a liquid is condensing.
___ 3. Water vapor can get into the atmosphere by evaporation and condensation.
___ 4. Transpiration is rain, snow, sleet, and hail.
___ 5. Precipitation is rain, snow, sleet, and hail.
___ 6. Carbon atoms are found in the atmosphere in a gas called water vapor.
___ 7. Carbon atoms are found in the atmosphere in a gas called carbon dioxide.
___ 8. Photosynthesis is the process in which plants use the sun’s energy to make carbon dioxide and water into glucose.
___ 9. Animals obtain their carbon by breathing in carbon dioxide.
___ 10. When animals eat, the molecules may be broken apart in the process called cellular respiration.

44. Test Yourself True or False
___ 11. Photosynthesis takes carbon dioxide out of the atmosphere.
___ 12. Decomposition takes carbon dioxide out of the atmosphere.
___ 13. Nitrogen is the most abundant gas in Earth’s atmosphere.
___ 14. Nitrogen gas in the atmosphere is taken in by plants and used for photosynthesis.
___ 15. Nitrogen gas in the atmosphere cannot be used by plants or animals.
___ 16. Some bacteria are able to change nitrogen gas into a different molecule that plants can use.
___ 17. Animals eat plants or other animals to get the nitrogen they need.
___ 18. Animals return nitrogen to bacteria.
___ 19. Most phosphorus is found in the atmosphere.
___ 20. The phosphorus cycle is the slowest cycle.

45. Test Yourself Matching
___ 1. precipitation
___ 2. condensation
___ 3. evaporation
___ 4. transpiration
___ 5. photosynthesis
___ 6. cellular respiration
___ 7. decomposition
___ 8. combustion
___ 9. nitrogen-fixing bacteria
___ 10. phosphorus
breaks down glucose to provide carbon to animals
when a liquid changes to a gas
the release of water vapor from plants
when a gas changes to a liquid
the majority is found in rocks and soil
takes carbon dioxide out of the atmosphere
adds carbon dioxide at an increasing rate
returns carbon to the soil and atmosphere
change atmospheric nitrogen gas into a form that is usable by plants
when liquid water falls back to Earth

46. Test Yourself Fill in the Blank
water cycle evaporation transpiration
sun condensation cellular respiration
precipitation photosynthesis decomposition
combustion atmosphere bacteria
soil rock water
The __________________ of water vapor in the air into liquid droplets helps clouds to form.
Water vapor gets into the air by ____________________ and _______________.
When the water in clouds falls to Earth, it is called _______________________.
The movement of water from Earth into the atmosphere and back again is called the ________________________.
The energy to power the water cycle comes from the _________.
The proceses called ____________________ and ________________________ are very important in the carbon cycle.
__________________ is the process that bacteria use to cause the decay of dead organisms.
Humans have caused an imbalance in the carbon cycle through ______________.
_____________ convert nitrogen from the ________________ into a usable form for plants.
Most phosphorus can be found in ___________, ___________, and __________.

47. Test Yourself Answer the Following
Draw and explain the water cycle.
Explain what happens to the water vapor when it cools? What does it form?
The process where water is lost from the leaves of plants to the atmosphere is called transpiration. What are examples of water loss from humans?

48. Test Yourself Answer the Following
List and explain the 3 ways carbon is released from living things into the environment.
Explain how photosynthesis moves carbon from the environment into living things.
Explain how carbon is taken from the environment and can be used by a living organism. Be sure to explain how a carbon atom can end up in a:
plant
animal

49. Test Yourself Answer the Following
How is nitrogen gas returned to the atmosphere?
How do animals get nitrogen?
What would happen if all of the bacteria in the ground stopped working?
Why is the phosphorus cycle considered to be the slowest biogeochemical cycle?

50. THE END!!!