1. Cycles of Matter

2. Recycling in the biosphere
Remember:
Energy is NOT recycled
Matter IS recycled
Biological systems do not use up matter; they transform it.
In other words, the same molecules are passed around again and again within the biosphere.
We are breathing the same oxygen atoms that dinosaurs might have!

3. Biogeochemical Cycles
Recycle matter within the biosphere
Biological, geological, and chemical aspects of the biosphere are connected and continually recycled, or passed, from one organism to another and from one part of the biosphere to another
The two most important biogeochemical cycles are: the water cycle and nutrient cycles

4. The Water Cycle All living things require water to survive
Water moves between bodies of water, atmosphere, and land

5. Water Cycle Terms
During the day, the sun heats the environment, which causes water molecules to enter the atmosphere through evaporation or transpiration
Evaporation = Water changes from liquid to atmospheric gas
Transpiration = Water evaporates from the leaves of plants

6. Water Cycle Terms (Continued)
The warm, moist air filled with water vapors becomes cool as it rises.
This leads to condensation = water vapor (gas) turns into liquid water, forming clouds
Precipitation = the water droplets within the clouds become large enough to fall to Earth in the form of rain, snow, sleet, or hail

7. Water Cycle Terms (Cont.)
Surface Runoff
Most of the precipitation that falls to the Earth runs along the surface of the ground until it enters a body of water
Precipitation can also seep into the soil and enter plants through their roots
Once runoff enters a body of water or seeps into the ground, the water molecules will evaporate or transpire again

8. Water Cycle Condensation Precipitation Evaporation Transpiration
Run off
Seepage
Root uptake

9. Nutrient Cycles
Nutrients = all chemical substances that an organism needs to sustain life
Help organisms build tissues and carry out essential life functions
Like water, nutrients are passed between organisms and the environment through biogeochemical cycles.

10. Nutrient Cycles (Continued)
Nutrients are in short supply for most ecosystems
Recycling nutrients becomes essential for ecosystems to function
Keeps a constant flow
Prevents chemicals from reaching toxic levels of concentration
Three most important nutrient cycles are:
Carbon, Nitrogen, and Phosphorus cycles

11. The Carbon Cycle Carbon is the key ingredient of living tissue
Carbon is found in:
organisms,
oceans, air, and certain
types of rocks

12. The Carbon Cycle (Cont.)
CO2 (Carbon Dioxide)
Makes up atmosphere
Released into atmosphere by organisms breathing, volcanic activity, burning fossil fuels, and vegetation
Releases into ground through decomposition of organic matter
Taken in by plants in photosynthesis

13. The Carbon Cycle (Cont.)
There are four main processes involved in the carbon cycle:
1. Biological = photosynthesis, respiration, and decomposition
2. Geochemical = erosion and volcanic activity
3. Mixed Biogeochemical = burial and decomposition
4. Human Activities = mining, cutting & burning forest, burning fossil fuels

14. E. Steps of The Carbon Cycle
Carbon enters the atmosphere from breathing and combustion
Producers use carbon dioxide in photosynthesis.
These producers then release oxygen.
Animals inhale the oxygen and exhale carbon dioxide. Animals also feed on the plants. The animals and plants eventually die.
Decomposers eat the dead plants and animals. The carbon that was in animal and plants is then returned to the atmosphere as carbon dioxide.

15. CO2 in
atmosphere
Carbon Cycle
CO2 in ocean

16. The Nitrogen Cycle
All organisms require nitrogen to make amino acids (which are used to build proteins)
Nitrogen gas (N2) makes up 78% of Earth’s atmosphere
Not usable by most organisms
Nitrogen containing substances such as ammonia (NH3), nitrate ions (NO3-), and nitrite ions(NO2-) are found in waste from organisms and in dead and decaying organic matter
These are usable forms of nitrogen
Humans add nitrogen to the biosphere through nitrate (fertilizers)

17. The Nitrogen Cycle (Cont.)
Only certain bacteria can use nitrogen gas directly
Found in soil and on roots of plants called legumes (beans, peas, peanuts, etc.)
They convert it to ammonia through nitrogen fixation
Other bacteria convert ammonia into nitrates & nitrites
Producers use it to make proteins, and consumers eat producers and reuse nitrogen to make proteins
When organisms die, decomposers return nitrogen to soil as ammonia
Ammonia is taken up by producers (again)
Other soil bacteria convert nitrates into nitrogen gas through denitrification, which releases nitrogen back into the atmosphere

18. Nitrogen Cycle N2 in atmosphere NO3- & NO2- Nitrate & nitrite NH3
ammonia

19. Simplified Nitrogen Cycle
Organic wastes(from plants and animals) add nitrogen to the soil.
Bacteria in the soil convert the nitrogen into forms plants can use.
Plants use nitrogen in the soil to grow, develop, and produce seeds.
Plants are eaten by animals and people. The organic waste (which contains nitrogen) is returned to the soil again.

20. The Phosphorus Cycle Phosphorus is essential to living organisms
Forms part of life-sustaining molecules such as DNA and RNA
Phosphorus is not common in the biosphere
Does not enter the atmosphere
Exists on land in rock and soil minerals, and in ocean sediments
Phosphate is released as rocks and sediments gradually wear down
On land, phosphate washes into rivers and streams, where it dissolves and eventually makes its way to oceans

21. The Phosphorus Cycle (cont.)
Runoff/Collection:
Erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processes
Absorption/Consumption
Plants absorb inorganic phosphate from soils; animals obtain organic phosphorus when they eat plants and other animals
Decomposition/Release
Plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products