16a - biogeochemical cycles 2012 - shhs...

Biogeochemical Cycles Biogeochemical Cycles Biogeochemical Cycles Biogeochemical Cycles

NotesNotesNotesNotes

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NotesNotesNotesNotes

Topic: Biogeochemical Cycles NotesTopics, Concepts, Review Questions Information, Vocabulary, Main Points: YOUR NOTES

All ecosystems consist of biotic & abiotic components. Interactions occurring

between these parts are essential to make

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are essential to make it function as one unit.

�Solar energy is an important abiotic component of nearly every ecosystem.

Topics, Concepts, Review Questions Information, Vocabulary, Main Points: YOUR NOTES

When solar energy is converted into chemicalenergy:

1) used for essential life processes

2) much is lost as heat

3) travels in onedirection: from sun to producer to consumer

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direction: from sun to producer to consumer

4) photosynthesis constantly replaces lost energy from an ecosystem

Topics, Concepts, Review Questions

Information, Vocabulary, Main Points: YOUR NOTES

What is recycledwithin an ecosystem?

matter – anything that takes up space and has mass1) all chemicals that make up

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1) all chemicals that make up the earth, air, and organisms

2) chemicals cannot be created or destroyed, but they can be changed from one form to another


Ecosphere: �A totally enclosedecosystem

�Needs controlled light & temperature conditions

�Function without the

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�Function without the loss or gain of any matter

�The light provides the energy

�Microorganisms recycle the chemicals

The Ecosphere is a completely sealed ecosystem containing active microorganisms. Simply provide

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containing active microorganisms. Simply provide it with indirect natural or artificial light and warmth and the ecosystem will thrive without needing further attention. The light allows the micro algae to produce oxygen and food for the shrimp, which in turn produce carbon dioxide and nutrients for the algae to grow.

A zoo is A zoo is A zoo is A zoo is not a not a not a not a closed closed closed closed natural natural natural natural ecosystem ecosystem ecosystem ecosystem because because because because

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because because because because it it it it requires requires requires requires huge huge huge huge inputs of inputs of inputs of inputs of resourcesresourcesresourcesresources....



**** In natural

ecosystems, some matter is gained or lost (taken to or carried

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(taken to or carried from another ecosystem), but most matter is recycled.


Methods by which mattercan enter or be removed from an ecosystem: 1. Wind

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2.Water

3.Humans



Examples: •Wind carrying small particles and gases great distances.

•Water removing soil from one ecosystem and

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from one ecosystem and depositing it in an aquatic ecosystem.


What is a biogeochemical(BGC) cycle?

•Shows the flow ofchemicals between the environment and organisms in it

•Is essential to the

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•Is essential to the survival of all ecosystems

•Recycles matter over & over again



•Carbon-oxygen cycle, nitrogen cycle, mineralcycle (rock or phosphorus cycle), & the hydrologiccycle (water cycle)

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cycle (water cycle)

Generalized BGC Cycle

The major parts of the biosphere are connected by the flow of chemical elements & compounds. In many of these cycles, the biota plays an important role.

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important role. Matter from the Earth’s interior is released by volcanoes. The atmosphere exchanges some compounds & elements rapidly with the biota & oceans. Exchanges


**** Carbon/Oxygen

Cycle-out of balance

•Plants utilize CO2

from the atmosphere for photosynthesis.

•Compounds

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•Compounds produced by plants contain carbon and are called organic compounds.


Which element do plants produce as a waste product?

What organism is responsible for producing most of

Oxygen (O2)

Phytoplankton in our oceans:

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responsible for producing most of the O2 in our atmosphere?

Phytoplankton in our oceans:

�Free-floating plants that support most aquatic food chains

�Algae & cyanobacteria


Respiration: •Organic compounds are broken down and carbon dioxide (CO2) is released.

•Chemical formula is

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•Chemical formula is opposite of photosynthesis!


Most CO2 is produced during the process of burning:

Combustion – when compounds containing carbon (coal, oil, or wood) are burned; the carbon

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are burned; the carbon chemically combines with O2 and CO2 is released.

–CO2 released very quickly.


The use of CO2by plants during photosynthesis is a much slower process.

As a result, the level of CO2 in the atmosphere is increasing due to this imbalance of the carbon-oxygen

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this imbalance of the carbon-oxygen cycle.

CarbonCarbonCarbonCarbon----Oxygen CycleOxygen CycleOxygen CycleOxygen Cycle

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CarbonCarbonCarbonCarbon----Oxygen CycleOxygen CycleOxygen CycleOxygen Cycle

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What happens when organisms die?

•Decomposers break down the carbon (C) compounds in their bodies.•Carbon dioxide is returned to the atmosphere.•During decomposition

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•During decomposition(decay), other chemicals are also returned to the soil or released into the air.•One of these chemicals is nitrogen (N2).

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Why do plants and animals need nitrogen? - to make protein

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Nitrogen gas makes up 78% of our atmosphere.

- But plants & animals cannot utilize it by breathing it in.

- This is why the N2

cycle is essential.



****

Nitrogen Cycle

A certain group of bacteria is essential to this cycle.

nitrogen “fixers”– bacteria in the soil & water change or “fix” N gas into

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change or “fix” N2 gas into nitrogen fertilizers [nitrate ions

(NO3-) or ammonium ions (NH4+)] that plants can use: nitrification

– live in nodules on the roots of plants called legumes

Rhizobia (microbial bacteria) on the Root Hair of a Clover Rhizobia (microbial bacteria) on the Root Hair of a Clover Rhizobia (microbial bacteria) on the Root Hair of a Clover Rhizobia (microbial bacteria) on the Root Hair of a Clover

Plant: MutualismPlant: MutualismPlant: MutualismPlant: Mutualism

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The Rhizobium nitrogen “fixer” makes threads that firmly attach to the root

hair.


How do animals get nitrogen? - by eating plants

or plant-eating

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nitrogen?or plant-eating animals in the form of protein



How is nitrogen recycled?

- special bacteria break down the nitrogen compounds (proteins) in dead plants & animals and in

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dead plants & animals and in animal wastes

- bacteria convert unusedfertilizer into N2 gas and release it into the atmosphere: denitrification



What other things play a role in the

�Lightning–Electrical energy combines N2 and O2 in the atmosphere where it dissolves in

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role in the nitrogen cycle?

where it dissolves in rain and later enters the soil where bacteria convert it into nitrate fertilizer.



�Farming–To grow crops that require large amounts of nitrogen (corn), commercial fertilizers are added.

–Legume crops are planted to

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What’s another major source of N2?

–Legume crops are planted to take advantage of their natural abilities to fix nitrogen in soil.

Burning fossil fuels (leads to acid rain)

Nitrogen CycleNitrogen CycleNitrogen CycleNitrogen Cycle

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“If people cannot write well, they

cannot think well, and if they

cannot think well, others will do

their thinking for them.”

~ George Orwell~

Stop HereStop HereStop HereStop Here

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Work on the Nitrogen Cycle HandoutWork on the Nitrogen Cycle HandoutWork on the Nitrogen Cycle HandoutWork on the Nitrogen Cycle Handout


**** Hydrologic

CycleDescribes the movement and storage of H2O on our planet.

�the total amount of water never changes (law of conservation of matter)

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conservation of matter)

�winds transport water vapor in the atmosphere & influence climate

�the sun provides the energy for the water cycle


How does water re-enter the atmosphere?

1) evaporation – when the sun’s energy heats water changing it to water vapor.

2) transpiration – when

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2) transpiration – when water vapor diffuses out of the leaves of plants through openings called stomata.



For example… During the growing

season, as many as 500,000 gallons of water vapor may re-

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500,000 gallons of water vapor may re-enter the atmosphere through transpirationfrom one acre of corn.



What happens when warm, humid air rises?

It loses energy, causing the air (water vapor) to coolwhere it collects on small particles in the atmosphere called condensation nuclei. These tiny droplets that

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rises?called condensation nuclei. These tiny droplets that form on the surface of these particles form clouds. This process of water vapor changing back into its liquid form is called condensation.

Think About It !What happens when you take a soda can from the refrigerator on a hot summer day? Can you explain what actually happens

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explain what actually happens when the can “sweats”? What process in the hydrologic cycle is occurring on the surface of

the can? 38


When water droplets become too heavy to remain in the atmosphere: They fall as rain,

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atmosphere: They fall as rain, snow, sleet, or hail

– precipitation.


Most of the earth’s surface is covered by water.

So most of the precipitation falls into the oceans or into other water bodies.

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water. bodies.

When it falls on land, it either enters the soil or becomes runoff.



What is infiltration?

The process of precipitation entering the ground.

�Taken up by roots of plants.

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plants.

�Percolates (moves down) through the soil and rocks until it reaches impermeable rock or clay –this water layer is called groundwater.

Water CycleWater CycleWater CycleWater Cycle

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**** The amount of

precipitation is an important factor in determining the type

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determining the type of ecosystem and the populations of organisms it can support.

16a - biogeochemical cycles 2012 - shhs...

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