Download Nitrogen Cycle

Nitrogen Cycle
TEKS 12 a
Objectives
1. Analyze the flow of energy through the
Nitrogen Cycle and Phosphorus.
2. Analyze changes caused by human and
natural occurrences in these two cycles.
What is Nitrogen?
Nitrogen is a chemical element. Look
at the periodic table at the front of
the room.
1. What group is carbon in? ________
2. What is the atomic mass? ________
3. How many protons? __________
What is Nitrogen?
Where can we find nitrogen?
Since it is odorless, colorless and tasteless,
we often don’t realize that nitrogen is ALL
around us.
Raise your hand if you know what
percentage of the air around you is
Nitorgen….
Did you guess it??
•75
Nitrogen Cycle
Nitrogen is important to all life!!
From the depths of the ocean ….
Nitrogen Cycle
To the atmosphere around us…
Nitrogen Cycle
We know Nitrogen is found in the air, but
where are some other places we can find
it?
1. In living Tissue
2. In proteins
3. In chemicals (ex: ammonia, nitric acid)
Nitrogen Cycle
Nitrogen in the atmosphere cannot be used
by most organisms. It has to go through a
special process first.
Nitrogen Cycle
Nitrification- Changing NH4 into NO2 or NO3
What does this mean??
Bacteria + Ammonia
Usable Nitrogen for Plants and
Animals
Nitrogen Cycle
Plants need nitrogen to
grow, develop and
produce seed.
The main source of
nitrogen in soils is
from organic matter.
Organic matter can be
plant and animal
residues.
Nitrogen Cycle
The nitrogen in organic matter is largely in
organic forms that plants cannot use.
Based on what you have learned so far,
what process has to happen before plants
can use the nitrogen?
Nitrification….
Bacteria found in soils
convert organic forms of
nitrogen to inorganic
forms that the plant can
use!
Nitrogen is taken up by
plant roots and combined
into organic substances
in the plant, such as
enzymes, proteins and
chlorophyll.
Nitrogen Cycle
When the plants die,
that organic material
goes back into the
soil and it may be
converted again!
How does nitrogen
leave the soil other
than through plants?
Nitrogen Cycle
DenitrificationBacteria change nitrate in the soil to atmospheric
nitrogen, which joins the atmosphere.
Runoff
Carries the nitrogen in fertilizers and manure
and the nitrogen in the soil into our rivers and
streams -- a concern for water quality.
Nitrogen Cycle
Another way nitrogen
enters the cycle is as
inorganic nitrogen
from the atmosphere
and factories.
• Make a thinking map to show the steps of
the nitrogen cycle
• You may include: pictures, labels and
descriptions.
• The next slide will help you…
Nitrogen Cycle
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7.
Cyanobacteria & Rhizobium take nitrogen from air
(nitrogen fixation)
Convert Nitrogen Gas into ammonia
Nitrifying bacteria in soil change ammonia into nitrates
Plants absorb and use nitrates to make proteins
Consumers eat plants and get proteins containing
nitrogen
Decomposers break down organic material and release
nitrogen to the air (called ammonification)
Anaerobic bacteria in soil release nitrogen from nitrates
into the air (called denitrification)
Phosphorus Cycle