Carbon

Carbon is one of the most important and versatile elements in nature. It is the only element that has a major field of chemistry devoted to the study of its compounds, organic chemistry. Most organic compounds come from living things, or once living things.

Carbon is the fourth most abundant element in the universe. Carbon atoms forged in the heart of aging stars. Most carbon on Earth is stored in rocks. The rest is in the ocean, atmosphere, living cells, soil, and fossil fuels.

Carbon has unique physical and chemical properties that make it capable of forming a wide variety of compounds, from simple molecules like carbon dioxide and methane to complex macromolecules like proteins and DNA. Carbon can form four covalent bonds (sharing of electrons to form electron pairs) with other atoms, allowing it to create different shapes and structures, such as chains, rings, and networks. Carbon can also form multiple bonds, such as double and triple bonds, with other carbon atoms or with atoms of other elements, such as oxygen, nitrogen, and hydrogen. That is how carbon is found in many forms in nature, such as graphite, diamond, coal, charcoal, and organic matter.

For instance, graphite and diamond are two allotropes of carbon. Allotropes mean they have the same chemical composition but different physical structures and properties. Graphite is soft, black, and metallic looking, while diamond is hard, clear, and shiny. Graphite is a good conductor of electricity and heat, while diamond is a good insulator. Graphite is used in pencils, lubricants, and batteries, while diamond is used in jewelry, cutting tools, and abrasives.

Carbon is the main component of organic molecules, that makes it essential for life on Earth. Carbon is present in all living organisms, from bacteria and plants to animals and humans. Carbon is involved in many biological processes, such as photosynthesis, respiration, metabolism, and synthesis of biomolecules. Carbon is also stored in various reservoirs on Earth, such as the atmosphere, the oceans, the soil, and the biosphere. The movement of carbon between these reservoirs is called the carbon cycle.

The carbon cycle is the process by which carbon moves between different reservoirs on Earth, such as the atmosphere, the biosphere, the oceans, and the geosphere. The atmosphere contains carbon in the form of carbon dioxide (CO2), which is a greenhouse gas that traps heat and regulates the Earth’s temperature. Carbon dioxide is exchanged between the atmosphere and other reservoirs through various processes, such as photosynthesis, respiration, or combustion. The biosphere consists of all living organisms on Earth, such as plants, animals, and microorganisms.

The biosphere stores carbon in the form of organic matter, such as carbohydrates, proteins, and fats. The biosphere takes in carbon dioxide from the atmosphere through photosynthesis, which converts light energy into chemical energy and produces oxygen. The biosphere releases carbon dioxide back to the atmosphere through respiration, which breaks down organic matter and releases energy and water. The biosphere also transfers carbon to other reservoirs through decomposition, which converts dead organic matter into simpler compounds, such as methane, carbon monoxide, and carbon dioxide.

The oceans contain carbon in the form of dissolved inorganic carbon, which is mainly composed of bicarbonate, carbonate, and carbon dioxide. The oceans absorb carbon dioxide from the atmosphere through air-sea gas exchange, which depends on factors such as temperature, salinity, and wind speed. The oceans also release carbon dioxide back to the atmosphere through the same process. The oceans also store carbon in the form of living and non-living marine biota, such as phytoplankton, zooplankton, fish, coral, and shells. The oceans transfer carbon to other reservoirs through the biological pump, which involves the sinking of organic matter to the deep ocean, and the carbonate pump, which involves the precipitation of calcium carbonate to the ocean floor.

The geosphere comprises the Earth’s interior, such as the mantle and the crust, and the surface, such as the rocks, minerals, and sediments. The geosphere stores carbon in the form of inorganic compounds, such as limestone, dolomite, and coal. The geosphere exchanges carbon with other reservoirs through geological processes, such as weathering, erosion, volcanism, and plate tectonics. Weathering and erosion dissolve and transport carbon from rocks and sediments to the oceans and the atmosphere. Volcanism and plate tectonics release carbon from the Earth’s interior to the atmosphere and the oceans through volcanic eruptions and subduction zones.

The carbon cycle is a complex and dynamic system that involves many interactions and feedbacks among different reservoirs and processes. The carbon cycle is also influenced by human activities, such as deforestation, land use change, and fossil fuel combustion, which have increased the amount of carbon dioxide in the atmosphere and altered the natural balance of the cycle. The carbon cycle is important for understanding the Earth’s climate and its changes over time. The fast and slow carbon cycles maintain a relatively steady concentration of carbon in the atmosphere, land, plants, and ocean. However, if anything changes the amount of carbon in one reservoir, the effect ripples through the others. In the past, the carbon cycle has changed in response to climate change. Variations in Earth’s orbit alter the amount of energy Earth receives from the Sun and leads to a cycle of ice ages and warm periods like Earth’s current climate. Today, changes in the carbon cycle are happening because of human activity.

Carbon as a free element by itself is harmless and considered nontoxic. On the other hand, carbon is threatening to life because it is a major contributor to global climate change because of the disturbances in the carbon cycle. Carbon cycle mechanisms are formed in the scale of billion years. The carbon released with the use of fossil fuels is basically releasing the energy trapped in the crust for millions of years in a relatively short amount of time. Without human interference, the carbon in fossil fuels would leak slowly into the atmosphere through volcanic activity over millions of years.

According to NASA, through a series of chemical reactions and tectonic activity, carbon takes between 100-200 million years to move between rocks, soil, ocean, and atmosphere in the slow carbon cycle. On average, 10^13 to 10^14 grams (10–100 million metric tons) of carbon move through the slow carbon cycle every year. In comparison, human emissions of carbon to the atmosphere are on the order of 10^15 grams, whereas the fast carbon cycle moves 10^16 to 10^17 grams of carbon per year. This energy release accompanied by carbon dioxide makes conditions more damaging. That is because, carbon dioxide is a greenhouse gas, meaning it helps to keep the earth warm retaining the heat from sunlight. Carbon dioxide also remains in the atmosphere for hundreds to thousands of years, affecting the temperature and weather patterns.

Carbon is a vital element that has many roles and impacts on our planet and our lives. Carbon is the basis of chemistry, biology, and technology, as well as a key factor in environmental and social issues. Carbon is a remarkable element that deserves our attention and appreciation.