Peat and coal are both part of the earth's carbon cycle. The carbon in peat and coals comes from carbon in wetland plants. More specifically, it originates in sugars formed from photosynthesis in wetland plants. The chemistry of photosynthesis can be shown in a formula as:

This means that carbon dioxide (CO₂) and water (H₂O) in plant tissues react with sunlight through photosynthesis to produce sugar (C₆H₁₂O₆) and oxygen (O₂).

Natural sugars are incorporated into biological molecules (carbohydrates, etc.) and are used to form plant tissues. When a plant dies, those tissues fall into the surface litter or water of the peat-forming wetland. Bacteria, fungi, and invertebrates break down the plant tissues. Some of the carbon in those plant tissues will be digested, and some will be transformed into gases that will escape to the atmosphere, but other carbon in partially decomposed plant tissues is preserved within the peat. If the peat is buried, the decomposed plant tissues and byproducts (and the carbon they contain) will be compacted. If the peat is buried deeply, it may become coal through the process of coalification.

Learn more

• Back to "Peatification"
• Back to "How Is Coal Formed?"
• Back to "What Is Coal?"