"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for Climate Mitigation"

The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.

Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.

By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.

In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.

1. CARBON CYCLE M.Mariselvam B.Sc., Department of Microbiology H.K.R.H. College, Uthamapalayam – 625533 Theni district.

2. Importance of carbon in living organisms Carbon is the main component of biological compounds such as carbohydrates, nucliec acids, lipids, proteins.

3. Reservoirs of carbon Carbon is present in the atmosphere as the gas carbon dioxide (CO2), which makes up approximately 0.04% of the atmosphere is the small actively cycled reservoir. It is also present in the ocean and fresh water as dissolved carbon dioxide. Carbons are also present in rocks such as limestone (CaCO3) and carbon present in fossil fuels include large slowly cycled reservoirs.

4. Role of microbes in carbon cycle Carbon transfer Carbon is exchanged between   heterotrophs  and  autotrophs  within and between ecosystems primarily by way of atmospheric CO 2 , a fully oxidized version of carbon that serves as the basic building block that autotrophs use to build multicarbon , high-energy organic molecules such as glucose. Photoautotrophs and chemoautotrophs harness energy from the sun and from inorganic chemical compounds, respectively, to covalently bond carbon atoms together into reduced organic compounds whose energy can be later accessed through the processes of  respiration  and  fermentation.

5. methanogenesis Bacteria and archaea that use methane as their carbon source are called  methanotrophs . Reduced one-carbon compounds like methane accumulate in certain anaerobic environments when CO 2  is used as a terminal electron acceptor in anaerobic respiration by archaea called  methanogens . Some methanogens also ferment acetate (two carbons) to produce methane and CO 2 . Methane accumulation due to  methanogenesis  occurs in both natural anaerobic soil and aquatic environments

6. acetogenesis Acetogenesis  is a process through which acetate is produced either by the reduction of CO 2  or by the reduction of organic acids. The different bacterial species that are capable of acetogenesis are collectively termed  acetogens . Reduction of CO 2  to acetate by anaerobic bacteria. Some acetogens can synthesize acetate  autotrophically  from carbon dioxide and hydrogen gas.

7. Biodegradation of biopolymers Microbes are responsible for maintaining the conditions of life as the earth by virtue of their powers of decomposition of plant and animal bodies by which the limited supply by C02 available for photosynthesis is replenished. Thus, they act as decomposers in the carbon cycle. Microbes mainly function as decomposers in the carbon cycle

8. Microorganisms that degrade cellulose can produce an enzyme called “ cellulase ” which catalyses the hydrolysis of the polymer to the dimer cellobiose . The latter is hydrolysed by the enzyme “ cellobiase ” to glucose which is absorbed by the decomposer or enters the soluble carbon pool.

9. The microorganisms that carry out this breakdown vary with the environment. Under aerobic conditions a wide range of fungi e.g., Chaetomium , Stacliybotrys , Trichoderma and Penicillium are important; some bacteria, e.g., Cytophaga , Bacillus, Pseudomonas may be the major decomposers of cellulose in aquatic environments

10. Some bacteria, e.g., Clostridium can degrade cellulose anaerobically and are therefore important in waterlogged soils and in deep water sediments.

11. GLOBAL WARMING Global warming refers to climate change that causes an increase in the average of Earth’s temperature. Natural events and human influences are believed to be top contributions towards the increase in average temperatures. Global warming is a rise in the surface and atmospheric temperature of the earth that has changed various life forms on the earth. The issues that ascertain global warming are divided into two broad categories – “natural” and “human influences” of global warming.

12. One natural cause of global warming is greenhouse gases. Greenhouse gases are carbon monoxide and  sulphur dioxide. It traps the solar rays and prevents them from escaping the surface of the earth. This causes an increase in the temperature of the earth. Volcanic eruptions are another reason for global warming. A single volcanic eruption can release a great amount of carbon dioxide and ash to the atmosphere. Increased carbon dioxide leads to a rise in the temperature of the earth.

13. Also, methane gas is another contributor to global warming. Methane is also a greenhouse gas. Methane is twenty times more effective in trapping heat in the atmosphere than carbon dioxide. Usually, methane gas is released from many areas like animal waste, landfill, natural gas, and others. Solar radiations striking Earth are returned back as Infra red rays. The increase in concentration of atmospheric carbon di oxide and other green house gases serves as an insulation blanket and trap these IR rays. This leads to global warming.

14. Thank you