Carbon Cycle Marta Gruzdova Sandy Kiamco Jalessah Jackson Block 3- APES

What is the importance? The concentration of carbon in living matter (18%) is almost 100 times greater than its concentration in the earth (0.19%). 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. Without the proper functioning of the carbon cycle, every aspect of life could be changed dramatically. Example: 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. Animals, such as the rabbit pictured here, 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. The carbon atoms in soil may then be used in a new plant or small microorganisms.

How the Carbon Cycle works 1) Carbon moves from the atmosphere to the plants. (from the sunlight through photosynthesis to the tree) 2) Plants to the animals. (cow eats the plants) 3) Carbon moves from the plant and animals to the ground, through decomposition. (the cow died and decomposed into the soil) 4) Carbon moves from living things to the atmosphere. (Animals and plants get rid of carbon dioxide gas through a process called respiration. Breathing releases CO2 into the atmosphere) 5 ) The burning of fossil fuels releases carbon into the air from the decomposed animals and the burning of plants. 6) The oceans intake the carbon from the atmosphere.

Interesting Facts: Each year, five and a half billion tons of carbon is released by burning fossil fuels. Carbon dioxide is a greenhouse gas and traps heat in the atmosphere. Without carbon and other greenhouse gases, Earth would be frozen. The atmosphere has not held this much carbon for at least 420,000 years. More greenhouse gases such as carbon dioxide in our atmosphere are causing our planet to become warmer, which contributes to global warming.

Over millions of years, the weathering of rocks on land can add carbon to surface water which eventually runs off to the oceans. Carbon is removed from seawater when the shells and bones of marine animals and plankton collect on the sea floor. These shells and bones are made of limestone, which contains carbon. Once deposited into the ocean, the carbon is stored on the seafloor. The carbon can be released back to the atmosphere if the limestone melts or is metamorphosed in a subduction zone.

The “missing” Carbon A carbon sink is anything that absorbs more carbon that it releases, while a carbon source is anything that releases more carbon than is absorb. The “missing” carbon is the removal of carbon from the atmosphere that is unknown to where it disappears. According to our textbook there are approximately 8.5 units released per year by human activities into the atmosphere, approximately 3.2 units remain in the atmosphere, and 2.4 units diffuse into the ocean. This leaves 2.9 unit unaccounted for.