Cycles of MatterCycles of MatterCycles of MatterCycles of Matter

December 7December 7thth, 2012, 2012

Energy

Energy is crucial to an ecosystem but organisms need more than energy to survive.

95% of the body is made up of oxygen, carbon, hydrogen, and nitrogen.

These elements are common on Earth but unless the elements are in a chemical form that cells can use, organisms cannot use them.

Recycling

Energy and matter move through the biosphere very differently.

Recycling

Matter is recycled within and between ecosystems from one organism to another and from one part to another

4 Cycles

• Water Cycle• Nitrogen Cycle• Phosphorus Cycle• Carbon Cycle

Nitrogen Cycle• Where is nitrogen found?

– The atmosphere is the largest sink and is 78% nitrogen

– The soil– In plants & animals as amino

acids

Nitrogen Cycle

Free Nitrogen in the atmosphere must be “fixed” from a gas (N2)to a useable substance.

Nitrogen The process by which nitrogen is

“fixed” to a useable form is called Nitrogen Fixation.

Nitrogen fixation is a complicated process that can happen by:

bacteria in plant roots decomposers in soil (bacteria) lightning forest fires.

Nitrogen is being “fixed” in both of these photos

Nodules (clumps) of bacteria hard at

work “fixing” nitrogen into plant

roots…

OTHER SNEAKY STEPS

Animal wastegives off nitrogen gas…

Decomposing bacteria release nitrogen as theybreakdown dead things.

HOW THE NITROGEN CYCLE WORKS

Denitrification: The escape of nitrogen into the atmosphere.

Phosphorus Cycle

Phosphorus is essential to all living organisms

Forms part of your DNA and RNA

Largest sink is the ground where it is stored in rocks and soil and released when they wear down

Phosphorus cycle

Carbon Cycle

Four Processes involved: Biological (photosynthesis and respiration)

Geochemical (volcanoes)

Mixed biogeochemical (fossil fuels)

Human activity (mining, burning fossil fuels)

Carbon Sinks• Most of the carbon is stored

underground

• The largest active sink for Carbon dioxide is the oceans. They absorb most manmade carbon dioxide.

• The Carbon dioxide concentration of the Earth’s atmosphere is 387 ppmv or 0.0387%.

Carbon Cycle

Carbon DioxideCarbon will combine with oxygen to form carbon dioxide

Plants

Take in Carbon Dioxide (CO2) and release oxygen gas (O2) in the process of photosynthesis

Photosynthesis

Remember that in a chemical reaction that…

Reactants → Products

In photosynthesis, carbon dioxide and water react in the presence of sunlight to form oxygen and glucose.

PhotosynthesisThe formula for photosynthesis is

Carbon dioxide + water → oxygen gas + glucose

We can balanced the equation and substitute the correct chemical symbols and it looks like…

6 CO2 + 6 H2O → 6 O2 + C6H12O6

Cellular Respiration

How do we get the energy that our cells need?

We eat to provide energy for our cells which in turn use that energy to carry out their jobs.

When the cells “burn” glucose for energy, the process is called cellular respiration.

Cellular RespirationOur cells take in oxygen and glucose from the

blood stream to use as energy and produce carbon dioxide and water as products.

We can balanced the equation and substitute the correct chemical symbols and it looks like…

6 O2 + C6H12O6 → 6 CO2 + 6 H2O

Does this look familiar?

Paired processes

Why do you think Photosynthesis and cellular respiration are considered paired processes?

Photosynthesis6 CO2 + 6 H2O → 6 O2 + C6H12O6

Cellular Respiration6 O2 + C6H12O6 → 6 CO2 + 6 H2O

• The end…