1. Chapter 3: Earth’s Environmental Systems
Biogeochemical Cycles

2. Biogeochemical Cycles
Bio-: Life
Geo-: Earth
Chemical: Substances like compounds or elements
Nutrients cycle through the interactions of living things and earth by going through a series of chemical reactions
Examples: Carbon Cycle, Nitrogen Cycle, Phosphorus Cycle

3. Law of Conservation of Mass
Matter can not be created or destroyed
It just changes form….
Water cycle…changes state
Biogeochemical cycles….changes into different compounds through different types of reactions

4. Nutrients Matter that organisms require for their life processes.
Macronutrients vs. Micronutrients
Nutrients required in
Large amounts like
Carbon, Oxygen,
Nitrogen and Phosphorus
Nutrients required in
Small amounts like
Potassium, Calcium,
Iron, etc.

5. Producer vs. Consumer
Primary producers produce their own food via photosynthesis
Plants, algae, phytoplankton (phyto- = plant)
Consumers are organisms that must eat (consume) other organisms (plant or animal) to obtain nutrients
Mostly animals
Decomposers are organisms that break down wastes and dead organisms
Bacteria and fungi

6. Food chains/Food webs
All of the substances that make up an organism is made of carbon…where does it come from?
Depends on what type of organism you are….

7. Food chains/Food webs

8. Carbon Cycle Also includes oxygen
Needed for energy
Also includes oxygen
Carbon is found in most of the compounds on earth…plastic, gasoline, carbohydrates, proteins, lipids, nucleic acids, etc….
A couple things to know in order to understand this cycle….
Food chains/Food webs
Producers, Consumers, and Decomposers
Photosynthesis
Respiration
Combustion
Decomposition
Fossil Fuels
Carbon Sinks vs. Carbon sources

9. Photosynthesis
Producers use solar energy to convert CO2 from the air into a usable form of carbon (glucose) that organisms can use for energy
(glucose)

10. Cellular respiration
Process by which ALL organisms use oxygen to release the chemical energy of sugars (glucose)

11. Decomposition All organisms die…where does their carbon go?
To the soil and eventually into rock (limestone) or as fossil fuels (coal or petroleum)

12. Fossil Fuels and Combustion
Fossil fuels are used by humans for energy through a process called combustion
This releases CO2 back into the atmosphere

13. Carbon Sinks vs. Carbon Sources
Sinks: Holds Carbons
Limestone and other sedimentary rock
Ocean
Plants: Land and Marine (phytoplankton/algae)
Permafrost: permanently frozen land
Sources: Releases Carbon back to atmosphere
Combustion: transportation, industry, etc.
Respiration
Volcanoes

16. Phosphorus Cycle Only involves the lithosphere (land)
Needed to
make
DNA and RNA
Only involves the lithosphere (land)
No atmospheric form
Think…
Fertilizer
Food chains
Runoff
Eutrophication

17. Phosphorus is bound up in rocks
Low amounts
Limiting factor of plant growth
Not needed as much as nitrogen…hangs out in water ways
Reason why it is main culprit of eutrophication

19. Eutrophication The effect is an overgrowth of producers (algae)
Eutrophication
Dead Zones Come Alive
The effect is an overgrowth of producers (algae)
Caused by runoff from fertilizer (high in nitrogen and phosphorus) as well as wastewater (phosphorus is found in detergents)
Can lead to hypoxia (low oxygen levels) from bacteria decomposing all the dead producers

21. Nitrogen Cycle Most abundant gas in atmosphere
Needed for proteins
Most abundant gas in atmosphere
Atmospheric nitrogen is unusable
Relies on bacteria to make it usable
Think…
Fertilizer
Legumes
Food chains
Bacteria: nitrogen fixation
Nitrification vs. Denitrofication
Lightning
Eutrophication

22. Nitrogen “fixing”
Nitrogen fixation: Conversion of nitrogen gas (N2) to ammonia (usable by plants)
Lightning
Nitrogen-fixing bacteria (found naturally in soil or in root nodules of legumes)
Nitrification: bacteria convert ammonia (NH3) into nitrites (NO2) then into nitrates (NO3)
Denitrification: denitrifying bacteria convert nitrates back into nitrogen gas (N2)

24. Secondary Nutrients Potassium Calcium Iron
Comes from weathered mineral salts
Needed for nerve function
Calcium
Needed for plant growth and shell formation
Iron
Needed for photosynthesis and transporting oxygen in blood