THE CARBON CYCLE 1 2 What is the Carbon Cycle? The Carbon Cycle is a complex series of processes through which all of the carbon atoms in existence rotate. 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. When you eat that plant, the same carbon from the wood which was burnt can become part of you. The carbon cycle is the great natural recycler of carbon atoms. Unfortunately, the extent of its importance is rarely stressed enough. Without the proper functioning of the carbon cycle, every aspect of life could be changed dramatically. 3 4 Plants and the Carbon Cycle Plants, animals, and soil interact to make up the basic cycles of nature. In the carbon cycle, plants absorb carbon dioxide from the atmosphere and use it, combined with water they get from the soil, to make the substances they need for growth. The process of photosynthesis incorporates the carbon atoms from carbon dioxide into sugars. 5 6 Animals and the Carbon Cycle Animals, such as rabbits, eat the plants and use the carbon to build their own tissues. 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, and when they die, since the carbon is returned to the soil during decomposition. There are also decomposers involved in the carbon cycle. They break down organic material such as dead animals, poop, or leaves. Decomposers are able to break down the chemical compounds inside the body. They also release carbon dioxide as well as methane. 7 8 Sometimes the decomposers don't break down organic material. There are great oil fields under the surface that are made of plants that did not decompose millions of years ago. There are also layers of rock made of millions of creatures who had shells. One day this carbon will return to the everyday carbon cycle, but geological processes are much slower than living processes Carbon is stored in the lithosphere in both inorganic and organic forms. Inorganic deposits of carbon in the lithosphere include fossil fuels like coal, oil, and natural gas, shale, and carbonate based sedimentary deposits like limestone. Since the Industrial Revolution, humans have greatly increased the quantity of carbon dioxide found in the Earth's atmosphere and oceans. Emissions from fossil fuel combustion account for about 65% of the additional carbon dioxide currently found in the Earth's atmosphere. Humans have altered the carbon cycle through fossil 9 fuel burning, deforestation, and land-use change. 10 Finally……. The same carbon atom can move through many organisms and even end in the same place where it began. Herein lies the fascination of the carbon cycle; the same atoms can be recycled for millennia! 11 Facts to Know!!! Producers are plants that take carbon dioxide gas from the atmosphere. Plants are producers. Plants use carbon dioxide to make energy in a process called photosynthesis. Consumers release carbon dioxide gas into the atmosphere as they burn sugar for energy. People and animals are consumers. They also release carbon to the atmosphere when they combust—burn—fossil fuels. Decomposers break down dead organisms and return carbon to the environment. Bacteria and fungi are decomposers. 12 Facts to Know!!! The source of carbon in fossil fuels comes from the remains of plants and animals that died long ago. Fossil fuels are oil, natural gas and coal. When we burn fossil fuels we put carbon dioxide back into the atmosphere. Too much carbon dioxide in the atmosphere can lead to an increase in the Earth’s temperatures, also known as global warming. 13