1. Life and Death, Nutrient Cycles
Cycles of Life
Life and Death, Nutrient Cycles

2. Nutrient Cycles Why do the nutrients on the Earth need to be cycled?
The Earth is considered a closed system.
This means that there is little or no input of new materials from outside the system.

3. Nutrient Cycles
Organics = H and C, often O and N (proteins, fats, sugars)
Inorganics – not containing C and H
Nutrients can be in the biotic environment or abiotic environment.

4. The Carbon Cycle
Plants make carbohydrates through a process known as photosynthesis.
6CO H2O + E  C6H12O O2
Capture of carbon from atmosphere
Carbon is returned to the atmosphere via cellular respiration.
C6H12O O2  6CO2 + 6H2O + E

5. The Nitrogen Cycle
Nitrogen is also very important and it will also circulate between the biotic and abiotic parts of the environment.
Proteins and DNA
Fertilizers contain N, P and K to facilitate growth
If there is no fertilizer then how does the plant acquire N?

6. Agriculture and Nutrient Cycles
Phosphate Accumulation
Algae growth = algal bloom
Bacteria break down algae and use oxygen to do so
Fish and animals die
Problems become worse