Name:



Name: _________________________________ Date: ______________________

Biogeochemical Cycles

Enviro 2 Go

6.1.1.1, 6.1.1.2

6.1.1.3, 6.1.1.4

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.

A BIOGEOCHEMICAL CYCLE is a circuit, or _______________________, by which an element or molecule moves through both ______________ and ___________________ components of an ecosystem.

We will study the following biogeochemical cycles:

• Water

• Carbon

• Nitrogen

• Phosphorus

Water Cycle

• Water is the basic building block of ____________________ on Earth.

• Water regulates the ___________________________ of the planet and cycles essential ______________________ through the biosphere and all living things.

• The flow of water through the biosphere is called the ________________________.

Important Vocabulary:

– Condensation

– Precipitation

– Evaporation

– Transpiration

Condensation

• The transformation of water ________________ to _________________ water droplets in the air, producing clouds and fog is known as __________________.

Precipitation

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

Evaporation

• ___________________________ is the process by which liquid water is _______________ by the __________ and rises into the atmosphere as ___________________________________ .

Transpiration

• ___________________________ is the ________________________ of water from the ____________________ of plants.

•

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.

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.

Question 1: How does water return to the earth?

Question 2: What is transpiration?

Question 3: How does water enter the earth’s atmosphere?

Carbon Cycle

• The carbon cycle is the biogeochemical cycle by which carbon is exchanged between the _______________________ and _____________________________.

• Carbon is an essential component of ____________________, ___________, and ____________________________ which make up all LIVING ORGANISMS.

Important Vocabulary

– Cellular Respiration

– Photosynthesis

– Decomposition

– Combustion

– Fossil Fuels

•

•

•

• Carbon exists in the Earth's atmosphere primarily as the gas _______________ ________________________ (_________).

• Carbon is taken ______________ the _____________________________ and returned to the Earth by the process ______________________________.

• Carbon can be released back into the atmosphere in many different ways, including:

–

–

–

Remember Photosynthesis?

Plants take _____________________________ from the _______________________, combine it with light energy and water to produce glucose and oxygen.

CO2 + H2O + light energy → C6H12O6 + O2

(__________________) + (_________) + light energy → (_________) + (___________)

Remember Cellular Respiration?

Cellular Respiration, performed by ____________ plants and animals, involves the breaking down of ________________ into _______________________ and water.

C6H12O6 + O2 → CO2 + H2O

(__________________) + (_________) → (_________) + (___________)

• The _____________________ is then released back into the _______________.

Decomposition

• _______________ is returned to the earth and released into the atmosphere through the _________________ of plants and animals.

• _______________________, such as fungi and bacteria, break down the carbon compounds in dead animals and plants and convert the carbon into _____________ ________________ in the presence of oxygen, or methane if oxygen is not present.

Combustion

________________________ is the burning of ______________________ such as coal, oil, and natural gas. Combustion ______________________ carbon that has been stored in the Earth’s crust for millions of years into the atmosphere as _________ ___________________.

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

Humans Affects on the Carbon Cycle

• ________________________ (burning fossil fuels)

– Driving their cars A LOT!

• Deforestation (destroying vegetation that ________________ carbon dioxide)

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!

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?

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 ____________________; however, it is in the form of nitrogen gas and is __________________ by most living organisms.

• Nitrogen is essential for many biological processes; and is crucial for any life here on Earth.

– Nitrogen helps build our __________________!

Important Vocabulary

– Legumes

– Root Nodules

– Nitrogen-Fixing Bacteria

• Nitrogen in the ________________________ is unusable to plants and animals.

• In order for nitrogen gas to be usable, it needs to be “________________.”

– Nitrogen-fixing ___________________ create usable forms.

– _______________________ also “fixes” atmospheric nitrogen.

Nitrogen-Fixing Bacteria

• _____________________ Nitrogen-fixing bacteria, there would ________ be enough usable nitrogen available to living organisms.

– __________________________________ “fix,” or _______________ the nitrogen __________ from the atmosphere into a _______________ form for living organisms.

• Nitrogen-fixing bacteria ___________ on the __________________________ of _____________________.

– Legume plants include:

• The legumes provide __________________ for the bacteria while the bacteria provide ____________________ to the plant.

Human Impacts on the Nitrogen Cycle

• ____________________ global concentrations of nitrous oxide (N2O) creates _______________________.

• Increased use of _______________________ increases nitrogen runoff into our waterways and contributes to ______________________________.

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.

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?

Phosphorus Cycle

• The phosphorus cycle may also be referred to as the _________________ cycle.

• The phosphorus cycle is the movement of phosphorus from the _____________ to ___________________ and then back to the _________________________.

• Phosphorus is mainly found in __________, ______________, and __________.

• Phosphorus is essential for life.

– Component of __________

– Building block of our ___________ and ________________.

• Unlike the other cycles, phosphorus ________________ be found in _________ in the gaseous state.

• The phosphorus cycle is the _____________________ cycle.

• Phosphorus is most commonly found in ___________ formations and ocean sediments as phosphate salts.

• Phosphate salts that are released from rocks through _____________________ usually dissolve in soil water and will be absorbed by plants.

• ______________ absorb phosphates by ________________ plants or plant-eating animals.

• When animals and plants die, phosphates will return to the soils or oceans again during __________________________.

• 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.

Human Impacts on the Phosphorus Cycle

• Like nitrogen, increased use of __________________ increases phosphorus runoff into our waterways and contributes to ____________________________.

REMEMBER THIS!!!

• Most phosphorus is found in rocks and soil.

• The phosphorus cycle is the slowest cycle.

• Excess phosphorus contributes to eutrophication.

Question 11: Where is most phosphorus found?

Questions 12: What is phosphorus used for in humans?

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.

___ 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.

Matching

___ 1. precipitation

___ 2. condensation

___ 3. evaporation

___ 4. transpiration

___ 5. photosynthesis

___ 6. cellular respiration

___ 7. decomposition

___ 8. combustion

___ 9. nitrogen-fixing bacteria

___ 10. phosphorus

a. breaks down glucose to provide carbon to animals

b. when a liquid changes to a gas

c. the release of water vapor from plants

d. when a gas changes to a liquid

e. the majority is found in rocks and soil

f. takes carbon dioxide out of the atmosphere

g. adds carbon dioxide at an increasing rate

h. returns carbon to the soil and atmosphere

i. change atmospheric nitrogen gas into a form that is usable by plants

j. when liquid water falls back to Earth

Fill in the Blank

water cycle

evaporation

transpiration

sun

condensation

cellular respiration

precipitation

photosynthesis

decomposition

combustion

atmosphere

bacteria

soil

rock

water

1. The __________________ of water vapor in the air into liquid droplets helps clouds to form.

2. Water vapor gets into the air by ____________________ and _______________.

3. When the water in clouds falls to Earth, it is called _______________________.

4. The movement of water from Earth into the atmosphere and back again is called the ________________________.

5. The energy to power the water cycle comes from the _________.

6. The processes called ____________________ and ________________________ are very important in the carbon cycle.

7. __________________ is the process that bacteria use to cause the decay of dead organisms.

8. Humans have caused an imbalance in the carbon cycle through ______________.

9. _____________ convert nitrogen from the ________________ into a usable form for plants.

10. Most phosphorus can be found in ___________, ___________, and __________.

Answer the Following

1. Draw and explain the water cycle.

2. Explain what happens to the water vapor when it cools? What does it form?

3. 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?

4. List and explain the 3 ways carbon is released from living things into the environment.

5. Explain how photosynthesis moves carbon from the environment into living things.

6. 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

6. How is nitrogen gas returned to the atmosphere?

7. How do animals get nitrogen?

8. What would happen if all of the bacteria in the ground stopped working?

9. Why is the phosphorus cycle considered to be the slowest biogeochemical cycle?

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