Carbon Fingerprints – The Carbon CycleCarbon is in most things around us; people, plants, tree, soil, oceans, and even the air we breathe. There is only a certain amount of carbon in, on, and around the Earth. The total amount of carbon stays the same, it just changes from one form to another. This is called a cycle. The Carbon Cycle is the movement of carbon, in its many forms, between the biosphere (all of Earth’s living organisms, atmosphere (the gaseous envelope surround the Earth), hydrosphere (the Earth’s supply of water), and geosphere (the solid part of the Earth). The Carbon Cycle tracks the movement of carbon between 1) all living plants and animals, 2) the gas surrounding the Earth, 3) water, and 4) soil and rocks. Main pieces of the Carbon Cycle are the atmosphere, ocean exchange, fossil fuels emissions, and terrestrial exchange.

The AtmosphereLocate the Atmosphere in the diagram. Carbon dioxide is one of the greenhouse gases. Although we may think of the atmosphere as the area where exchange is primarily occurring, there is also a lot of carbon storage in the atmosphere. This is represented in the diagram by the square box and the number 800 shown near the word Atmosphere. The number 800 is the number of gigatons stored. Just a reminder, that a place where carbon is stored is called a sink. Carbon storage is also called sequestration. In addition to carbon storage in the atmosphere, much of the planet’s carbon exchange occurs in the atmosphere. The atmosphere not only stores carbon, but it also exchanges carbon back and forth between the ocean and the land. There are three main ways for carbon to enter or be removed from the atmosphere. They are through 1) ocean exchange, 2) fossil fuel emissions, and 3) terrestrial exchange.

Ocean ExchangeLocate the Ocean Exchange portion in the diagram. Ocean exchange is the cycling back and forth of the carbon between the ocean water, ocean sediments, and the atmosphere. The ocean is also a large carbon sink and stores quite a bit of carbon especially in the deep ocean. The ocean not only stores carbon but it also exchanges carbon back and forth with the atmosphere at the ocean’s surface. Notice that the arrow going into the ocean represents carbon being taken up from the atmosphere and the arrow going out of the ocean shows the carbon being released into the atmosphere.

Fossil Fuel EmissionsLocate the Fossil Fuel picture in the diagram. Fossil fuel emissions refer to the carbon released into the atmosphere as a result of burning fossil fuels. Some examples of fossil fuels are gas, oil, and coal. Fossil fuels were made from the decomposition of prehistoric organisms that lived a long time ago and were exposed to the necessary conditions for a very long (thousands and thousands, or even millions of years). Fossil fuels are nonrenewable resources because they take so long to replenish. The other activities included with the fossil fuels category are the manufacturing of cement and land use changes. Land use changes refers to land that once grew tress but was cleared for other activities such as growing crops, grazing, animals, or development. This process is called deforestation because the tress will not be replanted in this area. Although both trees and plants sequester carbon, trees store far more carbon than plants such as grass. The fossil fuels category is the only category in which carbon is released and none is taken up. Carbon moves only from storage to emissions in this process.

Terrestrial ExchangeLocate Terrestrial Exchange on the diagram. The term terrestrial refers to the land so terrestrial exchange portion refers to the exchanges that occur in association with the land, including interactions with plants and animals. The exchange of carbon to and from terrestrial sources happens in many ways. The uptake of carbon occurs within the plant biomass and soil. The process of photosynthesis by plants takes up carbon dioxide and releases oxygen. In addition, carbon is also taken up and stored in the soil. On the opposite side, carbon is released into the atmosphere through the process of respiration (breathing) and decomposition of dead organic material.