THE CARBON CYCLE What is the Carbon Cycle

THE CARBON CYCLE

What is the Carbon Cycle? n n n The Carbon Cycle is a complex series of processes through which all of the carbon atoms cycle. The same carbon atoms in your body today have been used in countless other molecules since time began. The wood burned just a few decades ago could have produced carbon dioxide which through photosynthesis became part of a plant.

What is the carbon cycle? n When you eat that plant, the same carbon from the wood which was burnt can become part of you. n The carbon cycle is the great natural recycler of carbon atoms. n Without the proper functioning of the carbon cycle, life as you know it would cease to exist because there is a fixed amount of carbon in the world.

Plants in the Carbon Cycle: They are Producers. They PRODUCE their own food n In the carbon cycle, plants absorb (take in) carbon dioxide from the atmosphere and use it, combined with water they get from the soil, to make the substances they need for growth. n This process of photosynthesis incorporates the carbon atoms from carbon dioxide into sugars—the food the plants (producers) use for energy.

Animals in the Carbon Cycle: They are Consumers. They CONSUME other plants and animals n Animals, such as rabbits, eat plants & use the carbon to build their own tissues. n Other animals, such as the fox, eat the rabbit and then use the carbon for their own needs. ¨ These animals return carbon dioxide into the air when they breathe, which is part of respiration. ¨ When they “burn” (metabolize) their food for energy, which is another part of respiration. ¨ When animals burn fossil fuels, it is called combustion. ¨ When animals die, the carbon is returned to the soil during decomposition.

Bacteria and Fungi in the Carbon Cycle: They are Decomposers. n There also decomposers involved in the carbon cycle, such as bacteria and fungi. n They break down organic material (anything living or once living) such as dead animals, poop, or leaves. n They also release carbon dioxide, as well as methane, to the atmosphere.

When decomposers can’t get the job done, what happens to the carbon from dead stuff? n Sometimes the decomposers don't break down organic material—all the living or once living stuff. n This organic material is made into fossil fuels over thousands of years with the help of heat and pressure from the inside of the earth where it is buried. The source of carbon in fossil fuels comes from the remains of plants and animals that died long ago. n These fuels—oil, natural gas, coal, etc, are being dug out of the earth and used, returning the carbon to the carbon cycle but much too rapidly leading to the increase in carbon dioxide in the atmosphere and global warming.

When decomposers can’t get the job done, what happens to the carbon from dead stuff? Continued n Since the Industrial Revolution, humans have greatly increased the quantity of carbon dioxide found in the Earth's atmosphere and oceans. n Emissions from fossil fuel combustion account for about 65% of the additional carbon dioxide currently found in the Earth's atmosphere. n Humans have altered the carbon cycle through fossil fuel burning, deforestation (cutting down of trees), and land-use change, such as from farming to building homes.

Finally……. n The same carbon atom can move through many organisms and even end up in the same place where it began. n Thus, lies the fascination of the carbon cycle: The same atoms can be recycled for millennia!

Facts to Know!!! n When we burn fossil fuels we put carbon dioxide back into the atmosphere. n Too much carbon dioxide in the atmosphere can lead to an increase in the Earth’s temperatures, also known as global warming. n http: //www. epa. gov/climatechange/kids/car bon_cycle_version 2. html