2. Cycling of matter
Section 3.4

3. Recycling in the Biosphere
Energy is harnessed by autotrophs and moves in a one way stream
Between trophic levels energy is lost
Matter, however can be recycled within and between ecoystems
Biogeochemical cycles

4. Processes involved in biogeochemical cycles
Biological processes
Any and all processes performed by living organisms
Eating, breathing, excreting
Geological processes
Volcanic eruptions, erosion, subduction

5. Processes involved in biogeochemical cycles cont….
Chemical and physical processes
Cloud formation, precipitation, running water, lightening
Human activity
Fossil fuels, farming, fertilizers, deforestation

6. The Water Cycle

7. How are transpiration and evaporation similar? How are they different?
Process which allows water to re-enter the atmosphere
Evaporation – physical/chemical process
Transpiration – biological process

8. Nutrient Cycles Nutrients are needed to sustain life - why?
Organisms need them to build tissues, carry out functions,
Nitrogen, carbon and Phosphorous essential for life
Oxygen participates in all of these cycles
What are nitrogen, carbon and phosphorous used for?
Nitrogen – nucleic acids and proteins
Phosphorous – DNA and RNA
Carbon – everything!!!!

9. Carbon cycle Key Steps Atmosphere – plants – animals
To atmosphere through respiration
Decomposers release CO2
Carbon can turn into rocks or into fossil fuels

10. Why does fossil fuel formation start as a biological process and end as a geological process?
Geological forces turn biological or organic matter into carbon containing rocks or fossil fuels

11. Nitrogen Cycle Key Steps Nitrogen fixing bacteria can harness N2
Legumes (peanuts)
Primary producers can make protein and nucleic acid
Decomposers release nitrogen back into ecosystem
Bacteria can release gas through denitrification
Lightening can ‘fix’ nitrogen

12. How do humans affect the nitrogen cycle?
Humans turn N2 in the atmosphere to fertiliser – apply to crops etc…
Excess can run into rivers, streams and oceans resulting in increased nitrogen levels

13. Phosphorus Cycle Not abundant Mostly found in rocks and minerals
Key Steps
Released through erosion
Some stays on land and is used by plants and animals
Others enter marine ecosystem – processed into biological compounds

14. Nutrient limitation
If there is ample light and water, the productivity of a primary producer may be limited by the amount of available nutrients
This can happen if only one nutrient is in demand
Limiting nutrient

15. Nutrient limitation in soil
Plant growth often limited by one or more nutrients
It is why farmers use fertilizers
Only thing not included is carbon – why?
Readily available in atmosphere

16. Nutrients in aquatic ecosystems
Oceans are nutrient poor compared to land
For example th the amount of Nitrogen in the ocean when compared to soil
Nitrogen common limiting nutrient in aquatic ecosystems
After heavy rain, run off from fertilized field can cause algal bloom – a dramatic increase in the amount of algae
Can lead to eutrophication