Earth Science/Biology Standard 7a. Students know the carbon cycle of photosynthesis and respiration and the nitrogen cycle.

What is nitrogen?  Chemical element N, atomic number=7  Colorless, odorless, tasteless, inert gas  Makes up 78% of the atmosphere  N 2,Dinitrogen gas, (Diatomic )

Why is it important?  Proteins and nucleic acids (DNA, RNA) in living organisms  Nitrogen gas (N 2 )-> cannot be used directly. * Animals get nitrogen from plants or animals that ate plants

Forms of nitrogen  Atmospheric Nitrogen: N 2  Nitrate :NO 3  Nitrite: NO 2  Ammonia: NH 4

What is the nitrogen cycle? The process by which nitrogen is converted between its chemical forms It can be carried out by both biological and non-biological processes Bacteria are key element of the cycle

Where does it go? AirSoilPlantsAnimalsSoil Microbes

Nitrogen fixation break apart N2  Atmospheric: lightning  Biological: bacteria  Industrial: great pressure and temperature

Atmospheric Nitrogen and Nitrogen Fixation Triple bond is very stable Nitrogen gas-  ammonia Mainly through bacteria

Bacteria Single celled Very small, microscopic

Nitrogen fixing bacteria Bacteria living in root nodules of LEGUMES (soybeans, peanuts, alfalfa) Bacteria living in soil and water

Assimilation  Plants  Nitrate->nitrite-> ammonium-> amino acids, nucleic acids  Ammonium-> amino acids, nucleic acids (in legumes)  Animals eat plants amino acids, nucleotides

Mineralization (ammonification)  Plant or animal dies, animal excretes waste  Bacteria convert organic nitrogen to ammonium

Nitrification  Bacteria convert ammonium to nitrate  nitrite-> nitrate->ammonium  Nitrate-> ammonium  Can seep into groundwater  Health problems  Environmental problems

Denitrification  Bacteria convert Nitrate to Nitrogen gas  Completes the cycle by returning nitrogen to the atmosphere

Increased Nitrogen emissions  Cultivation of legumes  Artificial fixation of nitrogen  Nitrogen oxide from cars and factories (greenhouse gas, destroys ozone layer)

In water…  Acidification  Eutrophication Too much nitrogen in the water (mostly due to runoff from land) -> more algae (algal blooms) -> take up oxygen-> affects other organisms (animal lives die)

Earth Science/Biology Standards 7c. Students know the movement of matter among reservoirs is driven by Earth's internal and external sources of energy

What powers the water cycle?

What drives photosynthesis? ( Carbon transfer: atmosphere->biomass)

The sun!

What type of energy is produced during cellular respiration and *decomposition?

What powers subduction zones? Energy transfer between hot interior and cool exterior

How?

Convection movement of molecules in liquids and gases, “flowing”

Coal Formation? Plants that died millions of years ago *Pressure by sedimentary rocks

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