Areas of Focus within The Ecology: Abiotic Factors Unit Abiotic Factors, Biotic Factors, The Big 7 Abiotic Factors, Organisms Range of Tolerance, Light,

New Biogeochemical Cycle: The Nitrogen Cycle.

Copyright © 2010 Ryan P. Murphy

• What will be studying a whole lot of in the next few days?
















• Yes, We will be studying concepts that have a lot to do with waste.


Nitrogen Cycle: The circulation of nitrogen.








• Video! The goal will be to try and make some sense out this confusing video.


• Video! The goal will be to try and make some sense out this confusing video.– We will watch it again at the end of class to see if

we understand any of it. It’s wacky.


• Video! The goal will be to try and make some sense out this confusing video.– We will watch it again at the end of class to see if

we understand any of it. It’s wacky.– http://www.youtube.com/watch?v=tSzLQojOItg&f

eature=iv&src_vid=Hghru0O7dDs&annotation_id=annotation_151343


http://www.youtube.com/watch?v=tSzLQojOItg&feature=iv&src_vid=Hghru0O7dDs&annotation_id=annotation_151343



• Everyone take a deep breath in and then breathe out.– 78% of what you just breathed in was Nitrogen

N2 gas– 78% of what you exhaled was… Nitrogen N2

gas.




gas.




gas.




gas.


• Nitrogen in the atmosphere is N2 gas which is doesn’t bond well with other molecules.


• Nitrogen in the atmosphere is N2 gas which is doesn’t bond well with other molecules.– Nitrogen forms triple bonds with itself.








• When nitrogen is “fixed”, it’s bonds are split with the other nitrogen. Now it has three arms to make new friends,


• When nitrogen is “fixed”, it’s bonds are split with the other nitrogen. Now it has three arms to make new friends like oxygen.


• When nitrogen is “fixed”, it’s bonds are split with the other nitrogen. Now it has three arms to make new friends like oxygen.


• When nitrogen is “fixed”, it’s bonds are split with the other nitrogen. Now it has three arms to make new friends like oxygen (NO2)

Bacteria


• Rain and precipitation bring the atmospheric Nitrogen to the ground.

• Rain and precipitation bring the atmospheric Nitrogen to the ground.

• Nitrogen fixing bacteria in the soil and on the root nodules of plants can fix the nitrogen.

• Nitrogen fixing bacteria in the soil and on the root nodules of plants can fix the nitrogen.– Fix means change its form so a plant can use it.












To Plant


To Plant


To Plant

• Plants can now use this new molecule to get the nitrogen they need to build proteins so they can grow, repair, and reproduce.


Oxygen

• Plants can now use this new molecule to get the nitrogen they need to build proteins so they can grow, repair, and reproduce.– With the help of nitrogen fixing bacteria


Oxygen



Oxygen



Oxygen

• All life requires nitrogen-compounds, e.g., proteins and nucleic acids.

• Air, which is 79% nitrogen gas (N2), is the major reservoir of nitrogen.

• But most organisms cannot use nitrogen in this form.

• Plants must secure their nitrogen in "fixed" form, i.e., incorporated in compounds such as: – nitrate ions (NO3−) – ammonia (NH3) – urea (NH2)2CO

• Animals secure their nitrogen (and all other) compounds from plants (or animals that have fed on plants).


























Animals get their nitrogen from eating plants. Or…




































• Eventually, plants and animals die.• Ammonia (NH3) / Decay / Waste

• When plants and animals die. – Nitrifying bacteria break down the nitrogen in

their tissues. (Nitrites NO2)



Some of thisnitrogen can go

back to the nitrogen fixing bacteria



Some of thisnitrogen can go

back to the nitrogen fixing bacteria

• Denitrifying bacteria can also change the NH3 Nitrate back to N2 Nitrogen gas

• When the nitrogen is denitrified, it then bonds with another nitrogen to form inert N2 gas in the atmosphere until the cycle repeats.


• When the nitrogen is denitrified, it then bonds with another nitrogen to form inert N2 gas in the atmosphere until the cycle repeats.

“We now get to hang out in

the atmosphere for a long

time.”











































• Four processes participate in the cycling of nitrogen through the biosphere: – Nitrogen fixation: Break apart N2 so it can join to

other atoms and be used.– Nitrification: Plants with bacteria take up

nitrogen.– Decay: Passes on through eating / waste.– Denitrification: Nitrogen returned to the air by

bacteria. • Happens with poor soil management.


















other atoms and be used.– Plants with the help of bacteria take up nitrogen.– Decay: Passes on through eating / waste.– Denitrification: Nitrogen returned to the air by




other atoms and be used.– Plants with the help of bacteria take up nitrogen.– Decay and waste passes on nitrogen– Denitrification: Nitrogen returned to the air by





bacteria.




bacteria.






• This is an example of poor soil conservation methods which leads to soil nutrient depletion.


• This is an example of poor soil conservation methods which leads to soil nutrient depletion.– The lost nitrogen in this runoff will be denitrified by

bacteria back to the atmosphere .


• This is an example of poor soil conservation methods which leads to soil nutrient depletion.– The lost nitrogen in this runoff will be denitrified by

bacteria back to the atmosphere .


• Manmade fertilizers also puts nitrogen into the soil. (Ammonia NH3)


• Manmade fertilizers also puts nitrogen into the soil. (Ammonia NH3)–Excess / poor management of nitrogen

can result in pollution.








Documents

Areas of Focus within The Ecology: Abiotic Factors Unit Abiotic Factors, Biotic Factors, The Big 7 Abiotic Factors, Organisms Range of Tolerance, Light,