The weathering of the stone (limestone) is a part of the carbon cycle. The carbonate in limestone is naturally eroded by rainwater. Rainwater naturally contains a weak acid known as carbonic acid. The non-weathered stone is darker and looks sharper. Acid rain contains stronger acids than carbonic acid and accelerates chemical weathering. Image by JSTuby. All Rights Reserved.
Carbon is a chemical element. It sits at number six at the Periodic Table, and its chemistry is found in organic, inorganic, and biochemical reactions.
When many people think of carbon, they may envision pencil lead or charcoal. Yes, that is carbon, but carbon is a lot more than just the obvious items we can see around us.
Because it is at the center of so many chemical reactions, from carbon dioxide to limestone—we may even take carbon for granted.
Carbon, however, is at the center of a reaction scheme called the Carbon Cycle.
Without the Carbon Cycle, life as we know it would be quite different.
What do you mean by a Carbon Cycle?Two Paths In Bio-Geochemistry
The carbon cycle is a chemical cycle that helps to regulate climate, geology and biology. There are two different paths: slow and fast. Both paths revolve about carbon dioxide and water.
- Slow Cycle: Over geological time periods, carbon dioxide dissolves in fresh water and falls with rain and alters the environment.
- Fast Cycle: Carbon dioxide is incorporated by plant and animals in respiration (in biochemistry).
When taken together, the role of carbon on Earth becomes multipurpose — or sustains life.
In rain and snow, carbon dioxide dissolves in, and reacts with, water molecules to form carbonic acid (a weak acid). In the weathering process, carbonic acid reacts with limestone (calcium and magnesium carbonate) to produce magnesium and calcium bicarbonate. The bicarbonates, being much more soluble than the carbonates, wash out to sea and seep into the Earth’s crust, where volcanic heat re-releases the carbon dioxide to the atmosphere via volcanic vents. This re-released carbon dioxide combines yet again with water from the atmosphere, and the cycle repeats. Copyright image by Decoded Science, all rights reserved.
Carbon Slow Path–Geochemistry?
When fresh water (such as rain or snow) reacts with the carbon dioxide that is already a part of the fresh water, it produces a rather weak acid known as carbonic acid. This weak acid slowly dissolves rocks or pebbles in a process known as weathering. The stones release magnesium carbonates, calcium carbonates, potassium carbonates, and sodium carbonates in the process. The dissolved elements eventually reach the ocean, where they combine with other components of the water and eventually sink to the bottom. Some of the dissolved carbonates seep through the ocean floor to eventually vent through volcanic activity. Then, the vented carbon dioxide re-joins the clouds –it falls again with the rain.
This cycle is a part of our planet, and has been for thousands of years.
Carbon Fast Path–Life?
The fast path is generally measured with biological lifespans.
Carbon is known for its ease of forming bonds (with itself). The self-bonding of carbon atoms allows functioning DNA and other biological chemistry to happen.
The carbon cycle extends to Biochemistry as plants take carbon dioxide to generate oxygen and sugars. The reverse reaction plays a major role in the carbon cycle too. Taken together, we gain a perception our planet is alive. Copyright image by John A. Jaksich All Rights Reserved.
All living things need carbon –whether as bone (calcium carbonate), or in DNA or other chemical components—we use carbon as a part of life.
One case, the trees and plants utilize carbon dioxide in photosynthesis to convert the carbon from the atmosphere to plant sugar and plant components.
Once the animal life uses the plant feedstocks, it returns to once again to the Earth (soil, water and sky).
More importantly, when life ‘dies,’ we witness a release of carbon dioxide to the atmosphere through decomposition. Further considerations allow us to realize: animals, insects and people need the carbon cycle – we act together (in a synergistic manner) to keep our planet in sync.
Plant sugars (carbohydrates) are used throughout the plant and animal kingdoms. The process could be looked upon as the reverse of photosynthesis. Copyright Image by John A. Jaksich. All Rights Reserved.
Non-Normal Paths in the Carbon Cycle?
We can add extra carbon to cycles with carbon dioxide and with a host of molecules. Molecules like sulfur dioxide with nitrogen oxide(s) make can make the carbon cycle function abnormally. Sulfur dioxide and nitrogen oxide(s) complicate the carbon cycle with the further dissolution of stone, rocks, and cement. These solid materials deteriorate with acid rain in a manner similar to carbonic acid.)
Adding extra carbon dioxide to the atmosphere affects the cycle – there is more carbon dioxide than normal. When we speak of non-normal, we imply that the amount of carbon has not changed, but there is an abnormal amount of carbon dioxide (CO2).
The landscape–trees, flowing water, mountains, temperate climate — is shaped by the carbon cycle. Image by Skeeze.
Carbon: Not Destroyed, but Transferred
You cannot destroy carbon—it is ‘transferred’ from one form to another.
Looking at the scenarios closely, we see that carbon was changed from carbon dioxide to carbonic acid and sugar then back to the eventual beginning of carbon dioxide once more.
In the best of all worlds, we would not interfere with the carbon cycle by adding extra carbon dioxide or sulfur dioxide and nitrogen oxides, but we don’t live in that world.
Understanding the carbon cycle as an intimate part of life may eventually help our children to understand how approach the non-normal aspects of the carbon cycle.
Thank you so much-Vincent. The subject has many nuances that need so much more coverage. Thanks once again.
Thank you Vincent-
I did not know about the tie to climate— I found that extremely fascinating. Thank you so much for your comment.
A really nice article, I enjoyed the theme. The carbon cycle and the dissolution of the minerals made a great discussion.