The Nutrient cycle
Carbon Cycle
* Carbon EXISTS in abiotic environment as:
1. Carbon dioxide [CO2 (gas)] in the atmosphere dissolves in H2O to form HCO3-
2. Deposits of coal, petroleum, and natural gas
derived from once living things
3. Dead organic matter
* Carbon ENTERS biotic environment through:
1. Photosynthesis: changes light energy to chemical energy
* Carbon RETURNS to atmosphere by:
1. Respiration CO2
2. Decomposition / Decay
3. Burning fossil fuels
* Carbon Cycle and Humans:
1. Removal of photosynthesizing plants
2. Combustion of fossil fuels
Phosphorus Cycle
* Major environmental reservoir: rocks
1. Leaching: water dissolves phosphates in rocks and carries to lake, stream, etc.
2. Dissolved phosphate: used by plants and passed through food chain
3. Animals return phosphorus to environment by:
* excretion(Pooping)
* death and dead matter