Carbon (C)
Precisely what is carbon, and why does it play such an essential role in our climate, economy, and environment?
In its elemental form, carbon has an atomic number 6 and an atomic weight of 12; it has six protons with six neutrons in its nucleus, revolving 6 electrons around it. Carbon does not lose or gain electrons to form free ions, but it can form strong covalent bonds with many other elements. Carbon-hydrogen and carbon-oxygen bonds are exceptionally stable. Carbon is the 6th most abundant element globally, after H2, He, O2, Ne, and N2.
Carbon is an integral part of our life. It is there in every fossil fuel, limestone rocks, steel, dandelion plants to the nose on our face and the air we breathe. Carbon forms the backbone of DNA, floats through the air and water as CO2 and lays for millions of years in underground fossil fuels and limestone and dolomite rock.
It is also unique among the elements with the massive capacity of its atoms to bond to each other in long chains or rings due to the strength of bonds in between carbon atoms. Carbon generally crystallizes in two forms, (a) diamonds and (b) graphite. The three-dimensional result of long pure chains of carbon-carbon atoms is the diamond. When pure carbon chains include two sizes, the product is graphite, peeled apart easily in layers. Long chains/rings of carbon atoms exist in combination with hydrogen, oxygen, and nitrogen atoms and are known as organic compounds.
Carbon can forms covalent bonds with oxygen (CO2 and CO), hydrogen (methane), and nitrogen (hydrogen cyanide), and other molecules in a gaseous state. The atmosphere level of CO2 deposition increased by 30 percent since the advent of the Industrial Revolution. It was 275 parts per million in the early 1700s and more than 365 parts per million these days. Estimation shows that it will be to 450-600 parts per million by 2100. The primary cause of this is the fossil fuels combustion, Deforestation, Soli losing organic carbon due to changes in vegetation management and land use patterns, tillage process, and optimum utilization of natural resources.
Ocean sequesters the carbon dioxide as dissolved in seawater; carbon dioxide is converted into carbonate or bicarbonate. Specific forms of sea life biologically fix bicarbonate with calcium to produce calcium carbonate. This substance is used to create shells and other body parts by coral, clams, oysters, and other organisms. When sea creature dies, the calcium carbonate materials deposited to the ocean floor to form sedimentary rocks. So Ocean is the place where most of the carbon on Earth exists.
Carbon dioxide is not an excellent oxidizing agent, and it does not support the combustion of carbon-based substances. Instead, it extinguishes the discharge of these substances and is often used in fire extinguishers. Carbon monoxide is combustible. Organic compounds proteins, carbohydrates, and fats contain carbon. Carbon is combined with other elements in all biological substances is based upon compounds in which. Plant cells and animal tissue consist of carbon compounds and polymers.
Carbon is in inorganic and organic forms in Earth's crust. Carbonate minerals, carbonate formed with magnesium and calcium, are the most abundant and widely distributed minerals on Earth's surface. They are in the form of limestone, dolomite, and marble, and others. However, in terms of weight, oxygen, and silicon together are about 2,500 times more prevalent in the Earth's surface rocks than carbon. Carbon is widely distributed in the lithosphere.
Soil Organic Carbon
Carbon exists in the Earth's crust as soil organic matter. Microorganisms in the soil convert decaying organic matter and animal tissue/cells into soil organic components. It is estimated that there is 1500-1600 millions of metric tons of Soil organic carbon.
There are three types of carbon pools of Soil organic carbon:
a. Active
b. Intermediate or slow
c. Recalcitrant
Active
The active pool can stores carbon anywhere from a few months to a few years. The Active pool is less than 5 percent of the total soil carbon present.
Intermediate or slow
This type of pool can stores carbon for decades and accounts for 20 to 40 percent of total soil carbon.
Recalcitrant
The recalcitrant pool is exceptionally stable and stores carbon for hundreds or thousands of years before decomposing. Recalcitrant pool accounts for 60 to 75 percent of total soil carbon is in the resistant collection.
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