It’s Elemental:Exploring Environmental Health through Chemistry

The MIDAS Project: Supported by the Science Education Partnership Award Program of the National Center for Research Resources, National Institutes of Health (Grant No. R25 RR018634)

Earth Cycles

Elements exist in different forms in and around the earth. Certain elements such as nitrogen (N2), carbon (C), and oxygen (O2) move through Earth in cycles.

These cycles are necessary to help balance and regulate Earth and its atmosphere.

Changes in these natural cycles can be caused by human activities. Let’s see how these changes can affect the environment.

The Water CycleThe Water Cycle

http://geosurvey.state.co.us/wateratlas/images/thumb_fig2_2.jpg

The Water Cycle

Water (HWater (H22O) can change O) can change statesstates from solid to liquid to from solid to liquid to gas throughout its cycle. gas throughout its cycle. WaterWater can even change can even change straight from a straight from a solidsolid to a to a gasgas..

http://www.800mainstreet.com/1/0001-02-statesofmatter.html

For review of states of matter lesson, see Atoms Notes.

ChangesChanges in one part of the water in one part of the water cycle can cycle can affectaffect other parts of other parts of the cycle. When a the cycle. When a damdam is built or is built or a forest is cut down water is a forest is cut down water is diverted from its usual diverted from its usual routeroute. .

Mansfield Dam, Austin Texashttp://larae.net/photo/austin/

A dam A dam reducesreduces the amount of the amount of water moving down the river, water moving down the river, and cutting down a forest can and cutting down a forest can increaseincrease runoff and erosion as runoff and erosion as well as reducing the amount of well as reducing the amount of water returning to the water returning to the atmosphere from atmosphere from transpirationtranspiration. .

Transpiration animation

http://techalive.mtu.edu/meec/module01/Transpiration.htm

http://portal.unesco.org/education/en/ev.php-URL_ID=28912&URL_DO=DO_TOPIC&URL_SECTION=201.html

This can actually change weather This can actually change weather patterns. In addition, patterns. In addition, pollutantspollutants in in our water can harm both our water can harm both peoplepeople and other living things.and other living things.

http://www.popular-communications.com/hurricane%20copy.jpg

The The Carbon Carbon CycleCycle

http://i.treehugger.com/images/2007/5/24/timemagazine.jpg

http://www.kidsgeo.com/images/carbon-cycle.gif

All living things contain All living things contain carboncarbon (C). It is also found in (C). It is also found in waterwater, , airair and and soilsoil. As part of the . As part of the carbon cycle, carbon can carbon cycle, carbon can move from the Earth’s move from the Earth’s layerslayers to the atmosphere, the ocean, to the atmosphere, the ocean, into living things and back to into living things and back to the soil. the soil.

hydram.epfl.ch/VICAIRE/ mod_2/chapt_3/text.htm

One form of carbon, One form of carbon, carboncarbon dioxidedioxide (CO (CO22) is found ) is found naturally as part of the naturally as part of the atmosphere. Earth would be atmosphere. Earth would be frozenfrozen without carbon dioxide without carbon dioxide and other and other gasesgases. .

http://www.combatclimatechange.ie/uploadedfiles/Climate_Change_Facts/greenhouse%20effect%20from%20safeclimate%20site.jpg

Plants need Plants need carbon dioxide carbon dioxide for for photosynthesisphotosynthesis. . http://www.sinhhocvietnam.chttp://www.sinhhocvietnam.com/vn/modules/News/pic/113om/vn/modules/News/pic/1133729353_photosynthesis.gif3729353_photosynthesis.gif

When When fossilfossil fuelsfuels or trees or trees are burned, they are burned, they releaserelease excess excess carbon dioxide carbon dioxide into the into the atmosphere.atmosphere.

http://fireupdate.com/images/6.jpghttp://fireupdate.com/images/6.jpg

IncreasedIncreased amounts of amounts of carbon dioxide carbon dioxide are a cause for are a cause for global global warmingwarming and the changes and the changes in the Earth’s in the Earth’s climateclimate..

http://www.cosmosmagazine.com/node/825

Carbon Cycle Maphttp://www.windows2universe.org/

earth/climate/carbon_cycle.html

The Nitrogen CycleThe Nitrogen Cycle

http://www.visionlearning.com/library/modules/mid98/Image/VLObject-2068-030815020825.jpg

Our atmosphere is made Our atmosphere is made mostlymostly of nitrogen. It is necessary for all of nitrogen. It is necessary for all living living thingsthings to make amino acids to make amino acids into protein to become part of into protein to become part of their tissues as they grow. their tissues as they grow.

http://www.kidsgeo.com/images/earths-atmosphere.jpg

Most organisms cannot use Most organisms cannot use nitrogen nitrogen gasgas (N (N22) as it is found in ) as it is found in the atmosphere. It can only be the atmosphere. It can only be used once it has been used once it has been combined combined or “fixed”or “fixed” with other elements to with other elements to form compounds like form compounds like ammoniaammonia (NH(NH33) and ) and nitrate nitrate (NO(NO33). ).

Nitrogen is made usable by Nitrogen is made usable by lightninglightning, , or soil or soil bacteriabacteria,(in nodules or free ,(in nodules or free living) in a process called nitrogen living) in a process called nitrogen fixationfixation. .

http://www.insurevents.com/images/Lightning_strike.jpg

Animals get Animals get nitrogen from nitrogen from their their foodfood. . Most plants Most plants get nitrogen get nitrogen from the from the soil soil or wateror water. .

Releasing Nitrogen back intoReleasing Nitrogen back intothe Atmospherethe Atmosphere

Denitrifying bacteriaDenitrifying bacteria get energy get energy from decay of plants and animals from decay of plants and animals and convert Nitrogen and convert Nitrogen compounds into Nitrogen gas compounds into Nitrogen gas that gets released back into the that gets released back into the atmosphereatmosphere

Some farmers use nitrogen- Some farmers use nitrogen- containing containing fertilizersfertilizers to help to help plants grow larger and plants grow larger and fasterfaster. . The increased amounts of The increased amounts of nitrogen can flow into nitrogen can flow into riversrivers and streams as and streams as runoffrunoff. .

Dangers of too much Nitrogen

This causes This causes aquaticaquatic plants plants and algae to grow more and algae to grow more quickly, blocking quickly, blocking sunlightsunlight and and choking out fish and other choking out fish and other animalsanimals..

This causes This causes aquaticaquatic plants and plants and algae to grow more quickly, algae to grow more quickly, blocking blocking sunlightsunlight and choking out and choking out fish and other fish and other animalsanimals..

. Exhaust from burning fossil Exhaust from burning fossil fuels from vehicles and power fuels from vehicles and power plants put lots of Nitrogen into plants put lots of Nitrogen into the air which the air which combinescombines with rain with rain drops causing drops causing acid rainacid rain harming harming the organisms that live in waterthe organisms that live in water

It’s your planet!

Please take care

of it!