Carbon Sinks to Carbon Sources

Wetland Landscape

Of the myriad questions and answers to global climate change issues, many can be distilled down to carbon economics – how much is being put in the atmosphere versus how much is removed. Heavy on the minds of many are the lowering of emissions through technology and the essential roles played by forests and oceans in capturing and storing vast quantities of carbon. But beneath all of these, quite literally, is a carbon pool perhaps more dynamic than any other, and with immense consequences on climate change – namely, soils. Especially in northern Canada; boreal peatlands amount to 3% of the earth’s landmass while storing a third of global soil carbon. To put it in terms of carbon storage, every year boreal peatlands have the potential to capture and store about 13% of all carbon dioxide emitted by humans.

The soil microbiome is essential to turn decomposing organic matter into stable forms of stored carbon which cannot be easily released back into the environment.”

Close-up of Wetland Moss and LichenDictating the ability of Canada’s unique northern soils to act as a globally significant carbon sink are the dynamics of its seemingly-uncountable microorganisms. These microbial processes include the decomposition of organic matter from forests and agriculture, as well as a complex food-web of predators and prey – all of which is happening right beneath our feet. However, as the global climate is changing, these once-stable processes stand to change themselves, which will likely feedback on global climates. The water and nutrient dynamics of Canada’s soil systems are extremely vulnerable to warming climates; the soil biodiversity and food-web structures are dependent on stability to continue functioning as they are. With drastic shifts in climate as we are experiencing currently, and as the soil species dynamics change, carbon will be released from soils at rates much higher than it can be absorbed and stored long term. The carbon storage potential of soils may be entirely reversed, and these once-dependable carbon sinks will become sources of carbon themselves.

Zoë Lindo and her research group in the Department of Biology at Western University are investigating soil microbiological responses to changing climates. By investigating the effects of increasing temperatures on soil species composition and rates of organic decomposition, the Lindo group is contributing to global climate models that predict climate trajectories into the future.

Results

The Lindo lab has a long list of collaborations with provincial and federal ministries across Canada as well as the US Department of Energy. Policymakers, both in Canada and abroad, rely on these global climate models when implementing strategies to mitigate and/or reverse the effects of climate change. These models, in turn, rely on a detailed understanding of carbon dynamics. The often-forgotten, microscopic world beneath our feet forms a large portion of global carbon dynamics, and few systems are as globally influential as Canada’s boreal peatlands.