Biogeochemical CyclesBiogeochemical Cycles

Cycles We Will StudyCycles We Will Study

1. Water Cycle

2 Carbon Cycle

3. Nitrogen Cycle

4. Phosphorus Cycle

Law of Conservation of Matter-Law of Conservation of Matter-

Matter can neither be created

nor destroyednor destroyed

Reservoirs-

places where you can find the part of

the cycle you are interested in

Reservoirs-

places 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 groundLakes, ponds, ocean, the ground

Two Main Sources of EnergyTwo Main Sources of Energy

1. Internal energy from the core & radioactive isotope decay

2. External energy from the sun

The Water CycleThe Water Cycle

I. The Water CycleI. The Water Cycle

A.Precipitation- returning water to

the ground

Ex: rain, snow, sleet

B.Evaporation- change from liquid

to gasto 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 plantsfrom 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

The water cycle is

driven by energy from

the sunthe sunthe sun

What goes in your water cycle?What goes in your water cycle?

• The sun

• Precipitation

• Condensation• Condensation

• Evaporation

• Transpiration

• Groundwater

• Runoff

Water Cycle VideoWater Cycle Video

The Carbon CycleThe Carbon Cycle

II. Carbon CycleII. Carbon Cycle

A. Plants take in CO2 through stomata on their leaves

B. Plants use CO2 in

photosynthesis-

the process of making glucose

using CO2, water & sunlightusing CO2, water & sunlight

The equation for photosynthesisThe equation for photosynthesis

6CO2 + 6H2O � C6H12O6 + 6O2Sunlight &

chlorophyll

C. Glucose is . . .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 4. Animals return C to the

atmosphere through respiration.

D. How is C returned to atmosphere?D. How is C returned to atmosphere?

1. Exhalation

2. Decomposition

3. Burning

4. Burning of fossil fuels4. Burning of fossil fuels

5. Volcanoes

6. 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

Reservoirs to include in your Carbon cycle

drawing

• CO2 in atmosphere

• Burning

• Burning fossil fuels

• Plants

• Decomposition

• Water

• Volcanoes

• Don’t forget your • Plants

• Animals (exhalation, digestion)

• Don’t forget your arrows!!!!

Hannah Whitlock 2007

Carbon Cycle VideoCarbon Cycle Video

Global WarmingGlobal Warming

Global warming-the warming of the

earth by greenhouse gases emitted

into the atmosphere naturally or by

mankindmankind

**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 • When we add too many greenhouse

gases to the atmosphere we interrupt

the C cycle

Why is the greenhouse effect a problem?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 CycleThe Nitrogen Cycle

The Nitrogen CycleThe Nitrogen Cycle

A. Amino acids – contain nitrogen & C

and they make up proteins

B. There are 20 amino acids:

1. We make 121. We make 12

2. We get the other 8 from the

protein we eat

Plants need N to build proteinsPlants 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 2. The triple bonds must be broken so plants can use the N. This process is called N fixation.

N fixationN 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 legumes that have bacteria on their roots to fix N.

example: clover, peas, beans, & alfalfa

N fixation continuedN 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 NPlants & 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?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 VideoN Cycle Video

What goes in your N cycle?What goes in your N cycle?

• N2 in the atmosphere

• Lightening

• Legumes

• Fertilizer• Fertilizer

• Plants

• Animals

• Decomposition

• Denitirification

The Phosphorus CycleThe Phosphorus Cycle

PhosphorusPhosphorus

• 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 • 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

PP PP PP P

P

P

P

• Erosion can cause P-deficiency

• P fertilizers are often used

Why is the P cycle unique?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.

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