Nanoscale image of soil reveals ‘incredible’ world

May 1st, 2008 - 3:10 pm ICT by admin  

Washington, May 1 (IANS) When you look down at the grains of soil beneath your feet, all of them seem alike. But when scientists examined them very closely, at the nanoscale level, they discovered an incredible world populated by “heterogeneity of organic matter”. Outwardly, composition of organic soils from North America, Panama, Brazil, Kenya or New Zealand proved similar. However, spaces separated by mere micrometres within the same sample showed up striking differences during a recent study.

For example, compounds that “hang on the right and left of a clay mineral may be completely different”, said Johannes Lehmann of Cornell university, the co-author of the study.

“There is this incredible nanoscale heterogeneity of organic matter in terms of soil,” he said. “None of these compounds that you can see on a nanoscale level looks anything close to the sum of the entire organic matter.”

The researchers were also able to identify the origins of some of the nanosized compounds, determining that some of them, for example, were microbe excretions and decomposed leaves.

Knowing the structure and detailed composition of soil carbon could provide a better understanding of the chemical processes that cycle organic matter in soil, the study said.

For example, the research may help scientists understand what happens when materials in the soil get wet, warm or cool and how soils sequester carbon, which has implications for climate change.

“Now we can start locating certain compounds,” Lehmann said. “We find black carbon as distinct particles in pores, whereas we find microbial products smeared around surfaces of minerals.”

The study has been published in the April issue of Nature Geoscience.

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