1. Biogeochemical Cycles
Unit Objective
Students will be able to… Draw and label the water, carbon, and nitrogen cycles and explain what happens in each part of the cycle.

2. Matter and Living Things An Introduction to Environmental Chemistry
Brainstorm:
What do living things require?

3. atmosphere
temperature
energy
TWANE
water
nutrients

4. A Terrarium
A terrarium represents the components of an ecosystem and illustrates the fundamentals of energy flow.
Energy flow
Heat
energy
Light
energy
Chemical
energy
Chemical
elements
Bacteria,
protists,
and fungi

5. Ecosystems are supplied with a continual influx of energy from the sun and Earth’s interior.
Is that enough?
Student Misconceptions and Concerns
Students are unlikely to have any prior knowledge of biogeochemical cycles. Although some transfers between the biotic and abiotic components of ecosystems, such as the use of fertilizer on plants, may be known to them, the broader fact that the biosphere is a self-cycling system is not appreciated by most students. Before you lecture, consider asking your students to explain how carbon, phosphorus, and nitrogen cycle through the atmosphere. Pre-testing your students on their knowledge can confirm both what they understand and what they may need explained to them in more detail.
Teaching Tips
As you discuss the importance of the biogeochemical cycles, consider explaining the basic label information provided on a container of plant fertilizer. Consider an example that might be used on houseplants, and therefore more likely to be familiar to students. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, which are essential chemicals for growth.
Nope! So life on earth depends on the cycling of chemicals through the ecosystem. 5

7. The Major Earth Systems
Geosphere – land, rocks, earth
(Note: The surface land is called the lithosphere)
Hydrosphere – water (oceans, lakes, rivers…)
Atmosphere - air (78% N2, 21% O2)
Biosphere – all living and decomposing organisms

8. Cycling between them

9. Biogeochemical Cycles
Biogeochemical cycles is the flow of elements and compounds between biotic (living) components and abiotic (nonliving) components.
* reservoirs (or sinks)
Student Misconceptions and Concerns
Students are unlikely to have any prior knowledge of biogeochemical cycles. Although some transfers between the biotic and abiotic components of ecosystems, such as the use of fertilizer on plants, may be known to them, the broader fact that the biosphere is a self-cycling system is not appreciated by most students. Before you lecture, consider asking your students to explain how carbon, phosphorus, and nitrogen cycle through the atmosphere. Pre-testing your students on their knowledge can confirm both what they understand and what they may need explained to them in more detail.
Teaching Tips
As you discuss the importance of the biogeochemical cycles, consider explaining the basic label information provided on a container of plant fertilizer. Consider an example that might be used on houseplants, and therefore more likely to be familiar to students. Typically, plant fertilizers contain various forms of nitrogen and phosphorus, which are essential chemicals for growth.
compartments that store matter 9

10. Water Cycle

11. Terms Evaporation – liquid to a gas from the surface of a liquid
Condensation – gas collecting into clouds of water vapor
Precipitation – rain, sleet, or snow
Transpiration – evaporation of water from leaves
ground water – water that has seeped underground
Aquifer– water trapped and stored underground
Run off – water that follows the slope of land down to rivers, lakes and oceans

12. Interesting Facts about Water
There is a constant amount of water on and in the earth.
Only 3% of the water is “fresh”
70% of fresh water is frozen in glaciers.

13. We have energy and water – now what nutrients do we need?
Only about 24 elements!
Six of them are macronutrients.
The rest are micronutrients.
Ex: Calcium, Magnesium
We need them in large quantities!

14. CHNOPS What are the BIG SIX??? carbon hydrogen sulfur oxygen nitrogen
phosphorus

15. Elements that make up Life!!

16. CARBON
The Carbon Cycle
CO2
C6H12O6

17. So what is carbon in the real world?
Main ingredient in all organic molecules
Used by plants in photosynthesis
Used to compose carbon dioxide and all macromolecules
Graphite or diamond!
Can you name all three? Think back to Sports and Human Performance!

18. How do you think the levels of carbon stay in check in the environment?
Photosynthesis
The return of CO2 to the atmosphere by respiration closely balances its removal by photosynthesis.
Respiration

20. Respiration

21. The Carbon Cycle
Play the Carbon Cycle Game -

22. The Carbon Cycle
Continual movement of carbon atoms through organisms, oceans, atmosphere & crust
Atmosphere
as CO2
Biosphere
as proteins, sugars,
Hydrosphere
Geosphere
as CO2
As limestone fossils & fossil fuel

23. Where do we find the MOST carbon dioxide?
90% of Carbon Dioxide is stored in the ocean reservoir!

24. What disrupts this balance?
The burning of fossil fuels!
Combustion Reaction:
CH4 + O2  CO2 + H2O
Global Warming is a result of the excess CO2 in the atmosphere

25. Nitrogen – The Nitrogen Cycle
NH4+
NH3 N2
BACTERIA

26. Air (N2)  Nitrifying Bacteria  Plants  Animals  Decomposers  Denitrifying Bacteria  Air (N2)

27. Key Concepts
Nitrogen in the soil (think fertilizer and manure) help plants grow.
Plants get Nitrogen from the soil and excess nitrogen results in excess growth (to a point)
Crop rotation keeps the nitrogen levels in the soil at healthy.
Nitrogen is needed to make proteins – we get it by eating plants or eating animals that eat plants.

28. Bacteria are the Stars!
Bacteria take the nitrogen out of the air and put it in the soil
Other bacteria take the nitrogen out of the soil and puts it in the air
Without bacteria there would be no nitrogen cycle.

29. What happens when humans disrupt the Nitrogen Cycle?
Infertile land from using all the nitrogen up (this is why we have crop rotation)
Acid Rain from polluting gases
Algae blooms from fertilizer runoff into lakes and streams – These use up all the oxygen

30. Check for Understanding: Think, Pair, Share
What would happen if all the decomposers went on “strike” and stopped working? Which cycles would it affect and how?

31. These biogeochemical cycles is part of what makes a planet habitable
Connection to Space?
These biogeochemical cycles is part of what makes a planet habitable
EARTH: The most common elements in our atmosphere are nitrogen (78%), oxygen (21%), and argon (1%). The rest is comprised of very small amounts of neon, helium, methane, carbon dioxide, krypton, hydrogen, xenon, ozone, nitrous oxide, carbon monoxide, ammonia, and iodine. There is also water vapor in the lower part of Earth’s atmosphere.
Venus has thick clouds of toxic CO2.
Mars’s atmosphere is 95% carbon dioxide. The rest of it is nitrogen (3%), argon (1.6%), and very small amounts of water, methane, and oxygen.
The gas giants have methane (CH4).
“ices” – mixtures of compounds that include ammonia, ammonium, methane, and water.
Read more: