A carbon sink primarily absorbs carbon from the atmosphere through natural processes like photosynthesis by plants.
The Primary Mechanism: Plant Photosynthesis
One of the most significant ways carbon sinks, particularly forests, absorb carbon is through photosynthesis. As described in the reference:
"As plants photosynthesize, they absorb carbon dioxide from the atmosphere."
This fundamental process allows plants to take carbon dioxide (CO2), a greenhouse gas, from the air and convert it into organic matter, effectively removing it from the atmosphere and storing it within their tissues (leaves, stems, roots).
The Journey of Absorbed Carbon
Once absorbed by plants, the carbon follows a pathway:
- Absorption: Plants actively pull carbon dioxide out of the air during photosynthesis.
- Storage: The carbon becomes part of the plant's biomass, stored in its structure.
- Transfer to Soil: When plants die, the carbon goes into the soil.
- Potential Release: While stored in the soil, microbes can release the carbon back into the atmosphere through decomposition.
Carbon Sinks vs. Sources
It's important to understand that while some carbon is released back through processes like decomposition, a location is considered a carbon sink because it absorbs more carbon than it releases over time. Forests are classic examples of places that perform this crucial function for the planet's climate system.
Think of it like a balance: Absorption (like photosynthesis) adds carbon to the sink, while release (like decomposition) removes it. For it to be a sink, the absorption side of the balance must be greater.
