1. Biogeochemical Cycles

2. Cycling maintains homeostasis (balance) in the environment.
Nutrient Cycles
Cycling maintains homeostasis (balance) in the environment.
3 common cycles we will investigate:
1. Water cycle
2. Carbon cycle
3. Nitrogen cycle

3. Cycling of Matter Cycles in the Biosphere
Part 3: Cycling of Matter
Cycling of Matter
Cycles in the Biosphere
Natural processes cycle matter through the atmosphere
The exchange of matter through the biosphere is called the biogeochemical cycle.
Bio: Involves living things
Geo: Geological Processes
Chemical: Chemical Processes

5. Cycling of Matter The Water Cycle Solar Energy Solar Energy
Part 3: Cycling of Matter
Cycling of Matter
The Water Cycle
Solar Energy
Solar Energy
Movement of clouds by wind
Movement of clouds by wind
Precipitation
Precipitation
Evaporation
Evaporation
Precipitation
Precipitation
Transpiration from plants
Transpiration from plants
Percolation in soil
Percolation in soil

6. Cycling of Matter The Water Cycle
Part 3: Cycling of Matter
Cycling of Matter
The Water Cycle
Most precipitation falls into the ocean
Over land
approximately 90% of the water evaporates
10% transpires from plants
Only about 2% of water is retained in a reservoir
i.e., a glacier, ice cap, aquifer or lake

7. Nitrogen cycle-
Atmospheric nitrogen (N2) makes up nearly 78%-80% of air.
Organisms can not use it in that form.
Lightning and bacteria convert nitrogen into usable forms.

8. Nitrogen cycle-
Only in certain bacteria and industrial technologies can fix nitrogen.
Nitrogen fixation-convert atmospheric nitrogen (N2) into ammonium (NH4+) which can be used to make organic compounds like amino acids.
N2 NH4+

9. Nitrogen-fixing bacteria:
Nitrogen cycle-
Nitrogen-fixing bacteria:
Some live in a symbiotic relationship with plants of the legume family (e.g., soybeans, clover, peanuts).

10. Nitrogen cycle-
Some nitrogen-fixing bacteria live free in the soil.
Nitrogen-fixing cyanobacteria are essential to maintaining the fertility of semi-aquatic environments like rice paddies.

11. Cycling of Matter Nitrogen Cycle Part 3: Cycling of Matter Plants
Nitrogen in atmosphere
Plants
Assimilation
Denitrifying bacteria
Nitrates (NO3-)
Nitrogen – fixing bacteria in root nodules of legumes
Decomposers (aerobic & anaerobic bacteria and fungi)
Nitrifying bacteria
Ammonification
Ammonium (NH4+)
Nitrites (NO2-)
Nitrogen – fixing bacteria in soil

12. Nitrogen Cycle Atmospheric nitrogen Lightning
Denitrification by bacteria
Animals
Nitrogen fixing bacteria
Plants
Decomposers
Nitrification by bacteria
Nitrites
Nitrates
Ammonium

13. Cycling of Matter Carbon Cycle Part 3: Cycling of Matter
CO2 in atmosphere
Burning
Cellular Respiration
Photosynthesis
Plants, Algae & Cyanobacteria
Higher level Consumers
Wood & Fossil Fuels
Primary Consumer
Detritivores (soil microbes & others)
Detritus

14. Cycling of Matter Carbon Short term cycle
Part 3: Cycling of Matter
Cycling of Matter
Carbon Short term cycle
Autotrophs use CO2 for photosynthesis.
Heterotrophs produce CO2 during cell respiration

15. Cycling of Matter Long term cycle: Fossil Fuels
Part 3: Cycling of Matter
Cycling of Matter
Long term cycle: Fossil Fuels
Organic matter is buried underground and converted to peat, coal, oil or gas deposits.
5.5 billion tons are burned each year and 3.3 billion tons stay in the atmosphere
The rest dissolves in sea water turning oceans into mild acid

16. Cycling of Matter Long term cycle: Calcium Carbonate (CaCO3)
Part 3: Cycling of Matter
Cycling of Matter
Long term cycle: Calcium Carbonate (CaCO3)
Marine animals are able to use Carbon to build their skeletal material
These organisms fall to the bottom of the ocean floor, creating limestone rock.

17. Cycling of Matter Oxygen makes up about 21% of the atmosphere .
Part 3: Cycling of Matter
Cycling of Matter
Oxygen makes up about 21% of the atmosphere .
Very reactive element, quickly disappears in compounds
Some oxygen goes into the stratosphere, where it is converted into Ozone (O3)
Ozone serves to absorb biologically damaging ultra- violet (UV) radiation from the sun.

19. Cycling of Matter Carbon and Oxygen Cycles
Part 3: Cycling of Matter
Cycling of Matter
Carbon and Oxygen Cycles
Carbon dioxide (CO2) is a greenhouse gas and traps heat in the atmosphere.
Burning fossil fuels has added 30% more Carbon Dioxide than 150 years ago.
The atmosphere has not held this much Carbon for at least 420,000 years according to data from ice cores.