Oak Ridge National Laboratory scientists evaluating northern peatland responses to environmental change recorded extraordinary fine-root growth with increasing temperatures, indicating that this previously hidden belowground mechanism may play an important role in how carbon-rich peatlands respond to warming.
The team working at DOE’s whole-ecosystem warming experiment in northern Minnesota found that shrub fine-root growth increased linearly by 130% for every degree increase in soil temperature — a response 20 times greater than other ecosystems. This was driven by soil drying in the usually sodden peatlands, which store one-third of the world’s soil carbon.
According to published results, this response could explain why shrub coverage is increasing in these landscapes, which could shade out Sphagnum moss – a key species for carbon fixation in peatlands – and have downstream effects on peatland carbon storage.
“This work helps us understand a previously unknown aspect of these ecosystems, the world belowground,” said Avni Malhotra of Stanford University, formerly of ORNL.