Presentation on theme: "The Nitrogen Cycle. Why is Nitrogen Important? All organisms require nitrogen to live and build proteins Where is it found? 1.Free nitrogen gas 78% of."— Presentation transcript:
The Nitrogen Cycle
Why is Nitrogen Important? All organisms require nitrogen to live and build proteins Where is it found? 1.Free nitrogen gas 78% of atmosphere 2.In wastes, produced by organisms 3.In dead and decaying organisms Organisms must convert it to another form to use it
Nitrogen Fixation Nitrifying bacteria change free N 2 gas into nitrogen compounds that can be used by plants – Plants use them to make plant proteins – Animals eat the plants and use the proteins to make animal proteins – When plants and animals die, nitrogen compounds return to the soil
Denitrification Denitrifying bacteria in the soil break down these nitrogen compounds into free nitrogen, which is returned to the atmosphere
Nutrient Cycles Nutrients that are available in fixed quantities on Earth are passed from one organism to another and from one part of the biosphere to another. The amount of nutrients does not change, but the form might.