The Nitrogen Cycle Nitrogen, like water, is recycled through ecosystems over and over....

The Nitrogen Cycle

Nitrogen, like water, is recycled through ecosystems over and over....

Take a deep breath!

78% of the air you just breathed in is made up of nitrogen gas. Your body requires nitrogen tobuild proteins, amino acids, andDNA, but your body cannot use the nitrogen gas you just breathed in.

Look at the diagram on page 52 of your textbook to see where consumers like us (and the sheep in the diagram!) get nitrogen.

The Nitrogen Cycle

Nitrogen  a necessary building block of living organisms  used to make proteins, amino acids, and DNA

  found in atmosphere  78% of atmosphere is free nitrogen gas

(N2) cannot be used by most organisms

nitrogen fixation  nitrogen is "fixed" by combining with other  elements to form nitrogen-containing

compounds

  these compounds can be used by living things

  performed by certain kinds of bacteria

  nitrogen can also be fixed by lightning strikes

legumes  plants which contain nitrogen fixing bacteria in    nodules in their roots (e.g. clover, beans, peas,    alfalfa, peanuts)

Where do  plants take up simple nitrogen compounds fromproducers  the soil and use it to build proteins and other get nitrogen?  complex nitrogen compounds

Where do   consumers get nitrogen by consuming consumers producers or other consumers. getnitrogen? 

Good sources of protein(and therefore nitrogen)

Where do  by breaking down complex nitrogen compoundsdecomposers  in animal wastes and dead organismsget nitrogen?

  this process (decomposition) returns simple   nitrogen compounds to the soil.

How does  some bacteria break down nitrogen compoundsnitrogen  completely, releasing free nitrogen back intoback into the   the atmosphere.atmosphere? 

The Nitrogen Cycle

Nitrogen moves from the atmosphere to the soil, into living organisms, and backinto the atmosphere.

The nitrogen in your body might once have been in the body of a..

Wooly mammoth!

or a glyptodont! or maybe a giant ground sloth

or even Cleopatra!

And if you eat meat, some of the nitrogen making up your body was once part of the

body of whatever animal you ate!

The Nitrogen Cycle in an Aquarium

Forms of Nitrogen

1. Ammonia- (NH3) Waste product of animals released during excretion. Ammonia is toxic to most organisms.2. Ammonium- (NH4+) When ammonia is mixed with water, it grabs another hydrogen from the water molecules and makes ammonium. This is the only way you will ever see ammonia in nature. Also, it tends to stick to soil and clay particles instead of being washed away like nitrate.3. Free Nitrogen- (N2) This is a gas and is one of the most abundant gases in the atmosphere.4. Nitrate- (NO3-) This is usually found as a liquid and is very easily washed out of the soil and into groundwater or streams. Farmers don't like when their fertilizer gets turned into this, because it washes away too easily and isn't always in the soil long enough to help their plants.5. Nitric Acid- (HNO3) This is the form of nitrogen in acid rain. It is also made by lightning.6. Nitrite- (NO2-) This is a middle step during the process of nitrification. It is very toxic to organisms. In a new fish tank, nitrite can build up because the next step of nitrification can't continue until all the ammonium is gone, so you have to carefully measure NO2- when you first add fish to a tank.7. Nitrogen oxides- (N2O and NO) These are greenhouse gases and are a middle step (intermediate) between nitrate and N2 gas.8. Organic Nitrogen- (CaHbNcOd) Organic molecules containing nitrogen come in many forms from amino acids to proteins to lipids.