WASHINGTON, April 28 (Xinhua) -- Researchers from
Cornell University has looked "closely" at the soil for the first time -- at a
scale of 50 nanometers, revealing an incredible variety of organic compounds in
it, reported the April issue of Nature Geoscience which is available Monday.
"There is this incredible nanoscale heterogeneity of
organic matter in terms of soil," said Johannes Lehmann, lead author of the
study, in a statement on Monday. "None of these compounds that you can see on a
nanoscale level looks anything close to the sum of the entire organic matter."
The authors of the article said that knowing the
structure and detailed composition of soil carbon could provide a better
understanding of the chemical processes that cycle organic matter in soil.
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.
The nanoscale soil images were made at Brookhaven
National Laboratory using an X-ray spectromicroscopy method, which allowed the
researchers to identify forms of organic carbon in the samples.
While the composition of organic carbon in soils from
North America, Panama, Brazil, Kenya or New Zealand proved remarkably similar
within each sample, the researchers found that within spaces separated by mere
micrometers, soils from any of these locations showed striking variation in
their compositions. For example, the compounds that "hang on the right and left
of a clay mineral may be completely different," said Lehmann.
The researchers were also able to identify the
origins of some of the nano-sized compounds, determining that some of them, for
example, were microbe excretions and decomposed leaves. The researchers also
recognized patterns of where types of compounds are likely to be found at the
nanoscale.
The method now allows researchers to break soil down,
separate compounds, conduct experiments on individual compounds and better
understand the interactions, Lehmann said.
