Answer & Enrich Your Leaning:
Atmospheric carbon dioxide is the source of all carbon in both living organisms as well as in the fossils (used as fossil fuel). It is highly soluble in water. Oceans also contain large quantities of dissolved carbon dioxide and bicarbonates.
- Terrestrial and aquatic plants utilize CO2 for photosynthesis. Through this process the inorganic form of carbon is converted into organic matter in the presence of sunlight and chlorophyll. The carbon dioxide is thus fixed and assimilated by plants. It is partly used by them for their own life processes and the rest is stored as their biomass which is available to the heterotrophs as food.
- Respiration is a metabolic process reverse of photosynthesis in which food is oxidized to liberate energy (to perform the various life processes) and carbon dioxide and water. Thus the carbon dioxide of the atmosphere is recovered through this process.
- After the death of the organisms the decomposers break down the remaining dead organic matter and release the left over carbon back into the atmosphere.
- Fossil fuel such as crude oil, coal, natural gas or heavy oils on burning releases carbon dioxide and carbon monoxide into the atmosphere.
- Forests make a large amount of fossil fuel. Fossil fuel is product of complete or partial decomposition of plants and animals as a result of exposure to heat and pressure in the earth’s crust over millions of years.
- Forests also act like carbon reservoirs as carbon fixed by them cycles very slowly due to their long life. They release CO2 by forest fires.
Impact of human activities:
- Carbon dioxide is continuously increasing in the atmosphere due to human activities such as industrialization, urbanization and increased use of automobiles. This increase in atmospheric CO2 is bading to green house effect and global warming.