A study has found that fungi, and not plant matter as previously believed, is responsible for the majority of carbon sequestration in the northern taiga
The Taiga, or northern boreal forest, is the world's largest biome, stretching across the northern hemisphere and covering 11% of the earth's surface. It is responsible for a large amount of the oxygen produced on the planet, something which happens through carbon sequestration: When these forests absorb carbon dioxide, they discard the carbon before releasing the oxygen back into the ecosystem.
Until recently, it has been thought that trees were responsible for this process, but a new study from a group of scientists in Sweden have discovered that fungi are the actual cause. The group studied the soil on 30 islands in two northern Swedish lakes when they made the discovery.
Thank this little guy for the air you're breathing
A leading theory until recently has been that the carbon absorbed by plants was stored in leaves and needles which fall to the ground and eventually release the carbon through decomposition. If this was true, the scientists reasoned, the newest carbon deposits should be found in the top soil, near the surface. What they found, however, was that the carbon was being sequestered further down.
They found that the trees carry the carbon down through their roots via sugars, as opposed to through the leaves. Fungi often interact with trees through their root system, and it was found that a type of fungi called mycorrhizal fungi was consuming the sugars and expelling the carbon back into the soil.
The study found that in a soil sample from a large island, 47 percent of the sequestered carbon came from fungi. In a sample from a smaller island, the fungi were found to be sequestering 70% of the carbon. The team has been unable to determine why the discrepancy is so large, but they believe it may be linked to varying decomposition rates on the islands.