The Carbon CycleBy John Roberts and Adrian Rios

The Natural Pathway Photosynthesis: Carbon exists in the atmosphere as carbon dioxide.

It enters the food web when photosynthetic organisms, such as plants and certain algae, absorb carbon dioxide through their leaves. The plants capture the carbon dioxide and are able to convert it into simple sugars like glucose through the biochemical process known as photosynthesis. They are makers of their own food, and remove carbon dioxide from the atmosphere. When plants are eaten by animals, their carbon is passed on to those animals.

Respiration is the next step in the cycle occurs in plants, animals, and even decomposers. Respiration is the process in which oxygen is used to break down organic compounds into carbon dioxide and water. For an animal respiration is both taking in oxygen, and releasing carbon dioxide, and oxidizing its food in order to release the energy the food contains. In both cases, carbon is returned to the atmosphere as carbon dioxide.

The Natural Pathway (cont.) Decomposition is the largest source through which carbon is returned

to the atmosphere as carbon dioxide. Decomposers are microorganisms that live mostly in the soil but also in water, and which feed on the rotting remains of plants and animals. It is their job to consume both waste products and dead matter, during which they also return carbon dioxide to the atmosphere by respiration.

Weathering of rocks: Often carbon becomes trapped in limerock, a type of stone formed on the ocean floor by the shells of marine plankton. Sometimes after millions of years, the waters recede and the limerock is eventually exposed to the elements. When limerock is exposed to the natural process of weathering, it slowly releases the carbon atoms it contains, and they become an active part of the carbon cycle

National Reservoir The Earth’s Crust: The largest amount of carbon on Earth is stored in

sedimentary rocks within the planet’s crust. These are rocks produced either by the hardening of mud into rocks over geological time, or by the collection of calcium carbonate particles, from the shells and skeletons of marine organisms, into limestone and other carbon containing sedimentary rocks.

Oceans: The Earth’s oceans contain 38,000 Pentagrams of Carbon, most of which is in the form of dissolved inorganic carbon stored at great depths where it resides for long periods of time. A much smaller amount of carbon, approximately 1,000 Pg, is located near the ocean surface. This carbon is exchanged rapidly with the atmosphere

Atmosphere: The atmosphere contains approximately 750 Pg of Carbon, most of which is in the form of CO2, with much smaller amounts of methane and various other compounds. Although this is considerably less carbon than that contained in the oceans or crust, carbon in the atmosphere is of vital importance because of its influence on the greenhouse effect and climate. The relatively small size of the atmospheric Carbon pool also makes it more sensitive to disruptions caused by an change of C from the Earth’s other reservoirs.

Why is it so important? The Carbon in the air is very important, its what keeps the Earth

warm and from freezing.

The atmosphere is made up of .04% carbon and that percent is going up because of fossil fuels polluting the air.

Because there is more carbon in our atmosphere, the earths temperature is rising, causing global warming.

How the cycle is affected by LDCs and MDC’s

The carbon cycle is most affected by LDCs as they have factories that are releasing fossil fuels in the air.

LDCs like Brazil and Honduras, cut down trees for land, when the trees are cut down a major part of the carbon cycle is being skipped because there are less trees to take the carbon in and make carbon dioxide, this also leads to more carbon in the air which we know causes global warming.

MDCs such as America and Canada on the other hand don’t cut down trees as excessively or mine for coal, but they do release fossil fuels into the atmosphere through pollution but not as much as LDCs.

Pathway Affected by Human Activity

Since the start of the industrial age humans have harvested and burned deposits for energy, releasing the carbon compounds that were stored in the coal, oil, and gas deposits, much faster than they would have been released naturally, and this rapid release is the primary cause of global warming. Deforestation also decreases the amount of vegetation that can decrease the amount.