1. Biogeochemical Cycles

2. Carbon Cycle
1. Carbon can be found in different forms: gas in atmosphere, dissolved in water, fossil fuels, rocks, and soil.
2. Plants convert carbon dioxide in air into carbohydrates.
3. Organisms consume carbohydrates to get the carbon they need.
4. Processes: photosynthesis, respiration, burning of fossil fuels (combustion) release carbon back into the atmosphere.

3. Nitrogen Cycle 78% of the atmosphere is nitrogen gas.
Organisms cannot use N2 in the gas form
Most organisms can only use nitrogen when it is made into ammonia or nitrate.
Most of nitrogen cycle happens underground with special types of bacteria.
Process: nitrogen fixation (change nitrogen gas to ammonia), denitrification (nitrates are changed back to nitrogen gas)

4. Phosphorous Cycle
Most of phosphorus cycle takes place at ground level.
Phosphate is release by slow break down of rocks
Plants take up phosphates
Phosphorus then moves through the food chain/web.
Dead organisms are broken down, and release phosphorous back into the atmosphere.