(USA) Nitrogen pollution is choking forests’ carbon-protecting fungi

Shreya Dasgupta | Mongabay | 03/08/2018

  • Forests exposed to high nitrogen pollution in the U.S. are associated with low abundance of carbon-protecting ectomycorrhizal fungi, a new study has found.
  • The loss of these ectomycorrhizal fungi means that a lot of soil carbon is likely being released back to the atmosphere as carbon dioxide, accelerating climate change, researchers say.
  • The loss of ectomycorrhizal fungi could also mean fewer mushrooms and loss of potential antibiotics and other important biological compounds.

Under the forest floor lies a complex, hidden world of fungi. These tiny creatures form intimate connections with tree roots, sharing resources with each other and influencing the soil around them. Some of these are arbuscular mycorrhizal fungi, which dig deep into the root tissues. The other kind are ectomycorrhizal fungi, which grow outside, around the root filaments, producing many of the mushrooms that we see on the forest floor.

Ectomycorrhizal fungi also act as carbon guardians: they help slow down decomposition, and increase the amount of carbon dioxide locked away in trees and soil, out of the atmosphere. But excess nitrogen, produced by the burning of fossil fuels and the use of nitrogen-based fertilizers on farms, in the environment could be making these carbon-protecting fungi less abundant in forests, according to a new study published in Global Change Biology.