Most of my work has focussed on the above-ground parts of plants and ecosystems, but over the last few years, I have tutored PhD students in statistics and the use of the programming language R, and this has led to me being involved into some of their projects focussing on below-ground processes.
One of these projects, led by Anna Zakharova (who graduates later this month, congratulations!), looks at understanding the response of soil carbon (C) to disturbance and land management practices. Because soils are the largest pool of carbon (C) in terrestrial ecosystems (globally containing more than two-thirds of total ecosystem C), any changes in the soil storage can have dramatic consequences for the global storage/release of carbon and soil productivity (think global food crops!), not to mention the subsequent global warming due to increased CO2 in the atmosphere. But not all soil C is equal when it is predisposed to conditions where it may be lost. The portion called labile C (approximately 5% of the soil organic matter) is particularly vulnerable to being lost, because it is poorly protected by the soil particles, and microbes present in the soil will easily consume it when the soil structure is disturbed.
Until recently, it was really hard to measure how much labile C gets lost when you disturb a soil, and what determines the extent of the loss, but in a paper that was published online today, we tested whether a new method may do exactly that.
Zakharova A, Beare MH, Cieraad E, Curtin D, Turnbull MH, Millard P 2014. Factors controlling labile soil organic matter vulnerability to loss following disturbance as assessed by measurement of soil-respired δ13CO2. European Journal of Soil Science. doi: 10.1111/ejss.12209
As it turns out, the isotopic analysis of soil respired CO2 proved a powerful technique to improve our understanding of soil properties controlling potential loss of labile C after soil disturbance.