Nutrient Cycles

Form in which carbon exists in the atmosphere

• Carbon dioxide

• Carbon monoxide

• Chlorofluorocarbons

• Carbon Trioxide

Process that removes carbon dioxide from the atmoshere

• Photosynthesis

• Respiration

Process that produces carbon dioxide

• Photosynthesis

• Respiration

Three processes in plants and animals that return carbon dioxide to the atmosphere

• Respiration

• Photosynthesis

• Decomposition

• Combustion

Process during which fossil fuels release carbon dioxide in the atmosphere

• Respiration

• Combustion

• Photosynthesis

• Decomposition

Gas released into the atmosphere during photosynthesis

(a)  

Gas absorbed from the atmosphere during respiration

• Carbon dioxide

• Nitrogen

• Hydrogen

• Oxygen

Process during which lightning converts nitrogen gas into nitrates in the soil

• Nitrification

• Electrical fixation

• Denitrification

Organisms responsible for most nitrogen fixation

(a)  

Process during which dead organic material is broken down to release ammonia

• Nitrification

• Respiration

• Decomposition

• Denitrification