Biogeochemical Cycles
Cycles We Will Study
1. Water Cycle
2 Carbon Cycle
3. Nitrogen Cycle
4. Phosphorus Cycle
Law of Conservation of MatterMatter can neither be created
nor destroyed
Reservoirsplaces where you can find the part of
the cycle you are interested in
What is an example of a reservoir of water?
Lakes, ponds, ocean, the ground
Two Main Sources of Energy
1. Internal energy from the core &
radioactive isotope decay
2. External energy from the sun
The Water Cycle
I. The Water Cycle
A.Precipitation- returning water to
the ground
Ex: rain, snow, sleet
B.Evaporation- change from liquid
to gas
C.Condensation-change from gas to
liquid
D. Transpiration- water released to air
from stomata in plant leaves
E. Evapotranspiration- sum of water
evaporated and the water released
from plants
F. Run off- water that flows from higher
to lower places
G.Ground water- water found in the
ground that runs to a source like a
pond or spring
The water cycle is
driven by energy from
the sun
What goes in your water cycle?
•
•
•
•
•
•
•
The sun
Precipitation
Condensation
Evaporation
Transpiration
Groundwater
Runoff
Water Cycle Video
The Carbon Cycle
II. Carbon Cycle
A. Plants take in CO2 through stomata on
their leaves
B. Plants use CO2 in
photosynthesisthe process of making glucose
using CO2, water & sunlight
The equation for photosynthesis
6CO2 + 6H2O C6H12O6 + 6O2
Sunlight &
chlorophyll
C. Glucose is . . .
1. what our cell use for E
2. used to make starch & carbs
3. used to make cellulose in plants
4. Animals return C to the
atmosphere through respiration.
D. How is C returned to atmosphere?
1.
2.
3.
4.
5.
6.
Exhalation
Decomposition
Burning
Burning of fossil fuels
Volcanoes
The ocean is a reservoir for Carbon.
When calcium carbonate in limestone
& shells break down C is released.
Reservoirs to include in your Carbon cycle
drawing
•
•
•
•
•
CO2 in atmosphere
Burning
Burning fossil fuels
Plants
Animals
(exhalation,
digestion)
•
•
•
•
Decomposition
Water
Volcanoes
Don’t forget your
arrows!!!!
Hannah Whitlock 2007
Carbon Cycle Video
Global Warming
Global warming-the warming of the
earth by greenhouse gases emitted
into the atmosphere naturally or by
mankind
**CO2 is an example of a greenhouse
gas
• Greenhouse gases act as a shield
and trap heat inside the atmosphere.
• This process is necessary for life on
Earth.
• When we add too many greenhouse
gases to the atmosphere we interrupt
the C cycle
Why is the greenhouse effect a problem?
• An increase in the planet's temp may
cause the ice caps to melt and sea levels
to rise.
The Nitrogen Cycle
The Nitrogen Cycle
A. Amino acids – contain nitrogen & C
and they make up proteins
B. There are 20 amino acids:
1. We make 12
2. We get the other 8 from the
protein we eat
Plants need N to build proteins
1. N2 in the air can’t be used by plants
directly.
*N=N makes up 78% of the air
2. The triple bonds must be broken so
plants can use the N. This process is
called N fixation.
N fixation
1. N fertilizers take a lot of E to make &
plants only use about half of it. The rest
runs off into water supplies.
2. Instead farmers use plants called
legumes that have bacteria on their roots
to fix N.
example: clover, peas, beans, & alfalfa
N fixation continued
3. The bacteria change N2 to ammonia
which plants can use to make protein.
4. Lightning also causes N fixation
Plants & animals get N
• Plants absorb N through roots & leaves to
make necessary proteins.
• We eat plants & animals to put proteins &
amino acids in our bodies.
How is N returned to the system?
• N2 is returned to the atmosphere by
bacteria in a process called denitrification.
• Decomposition & Waste return N to the air
& to soil
• Fossil fuel use
Hannah Whitlock 2007
N Cycle Video
What goes in your N cycle?
•
•
•
•
•
•
•
•
N2 in the atmosphere
Lightening
Legumes
Fertilizer
Plants
Animals
Decomposition
Denitirification
The Phosphorus Cycle
Phosphorus
• Needed for the formation of bones, teeth,
& DNA
• We get P from food we eat
•
•
•
•
Most P in the world is in rocks
Weathered rock releases P to the soil
It is absorbed by plant roots.
Animals eat the plants to get the P
P is released to soil
• Animals return it to the earth by wastes &
decomposition
• Bacteria & decomposers return P to soil
• P can dissolve in ground water & be
carried back to a body of water
• Sediments settle in the body of water & cement
together to form P-rich rocks
P
P
P
P
P P
P P
P P
P
P
P
• Erosion can cause P-deficiency
• P fertilizers are often used
Why is the P cycle unique?
• P is not found in a gas form, so the
atmosphere is not involved.
• P cycle is very slow. It can stay in rocks
for millions of years.
ERROR: undefined
OFFENDING COMMAND: ;*Y:!;*Y:!;*Y:!;*Y::’Mnj.72,a
STACK: