We cannot overlook below-ground processes if we are to understand net carbon budgets on timescales relevant to the Climate Emergency. Understanding the fundamental mechanisms controlling the accumulation, stability, and loss of soil organic matter is as essential for predicting the Earth's future climate.
Professor Wookey and his team will carry out innovative experiments which will test whether vegetation change could turbo-charge the mycorrhizosphere - the microhabitat in soil where plant roots are surrounded by fungus – resulting in a net loss of carbon from soils to the atmosphere.
They will investigate how the presence of plant roots, and their associated mycorrhizal fungi, could accelerate the decomposition of pre-existing soil organic matter. Mycorrhizal fungi access nutrients from the soil for their plant hosts, however, some may increase soil carbon loss.
The team are setting up experiments at tree line areas of Arctic Sweden to work out which fungi are growing with pioneer trees and how much CO2 loss to the atmosphere they are causing. In the lab, the team will culture (or grow) these fungi and carry out more experiments to understand their role in soil decomposition.
By comparing these processes in contrasting vegetation communities, they can assess how ongoing and predicted changes in plant communities, from tundra heath to shrub and forest, would affect net ecosystem carbon exchange with the atmosphere.
Professor Wookey said: “Many high-profile research papers have equated Arctic greening with increased net carbon sequestration from the atmosphere. Although logical and intuitive, this overlooks the potential fate of pre-existing soil organic carbon in these regions. This is a problem because soils at high latitudes are notably carbon rich.
“Although challenging to investigate, we cannot overlook below-ground processes if we are to understand net carbon budgets on timescales relevant to the Climate Emergency. Understanding the fundamental mechanisms controlling the accumulation, stability, and loss of soil organic matter is as essential for predicting the Earth's future climate as understanding photosynthesis and plant productivity.
“We hypothesise that associated changes in the mycorrhizosphere could, paradoxically, result in net losses, rather than gains, of soil carbon. By applying groundbreaking techniques, we will transform our understanding of this process and the fundamental new knowledge gained will significantly improve regional and global modelling of climate change. This project is especially timely, given the major policy emphasis and public interest in tree planting for carbon sequestration.”
Dr Thomas Parker, a co-investigator at the James Hutton Institute, said: “There is growing evidence from the boreal forest that a small, but very important group of mycorrhizal fungi are centrally important for the carbon balance of forest soils. It is largely unknown as to what will happen when these fungi colonise the tundra. Filling in this gap could help better predict climate feedbacks.”
The study led by Professor Wookey is one of 44 environmental research projects awarded a share of £25m invested by the government to tackle significant questions about our planet.
A grant of almost £800,000 was made by the Natural Environment Research Council (NERC), one of seven research councils which make up UK Research and Innovation (UKRI), which is the national funding agency investing in science and research in the UK.
Professor Sir Duncan Wingham, Executive Chair of NERC, said: “This investment supports researchers’ curiosity and imagination to enable discoveries that unlock new knowledge. By supporting high risk, high reward environmental science, we are harnessing the full power of the UK’s research and innovation system to tackle large-scale, complex challenges.”
Professor Wookey’s study Turbo-charging the mycorrhizosphere - Could more productive ecosystems threaten soil carbon stocks in boreal and sub-arctic zones of transition? will run until October 2026.
Professor Wookey will work on the project with Drs Tom Parker and Andy Taylor (Co-Investigators, James Hutton Institute, Aberdeen); Dr Lorna Street (Co-Investigator, University of Edinburgh); Dr Mark Garnett (Project Partner, NEIF Radiocarbon Lab, University of Glasgow); Dr Karina Engelbrecht Clemmensen and Prof Björn Lindahl (Project Partners, Swedish University of Agricultural Sciences, SLU, Uppsala) and a Post-doctoral Research Associate (to be appointed).