Chemodiversity of Soil Dissolved Organic Matter

Dissolved
organic matter (DOM) plays a key role in many biogeochemical
processes, but the drivers controlling the diversity of chemical composition
and properties of DOM molecules (chemodiversity) in soils are poorly
understood. It has also been debated whether environmental conditions
or intrinsic molecular properties control the accumulation and persistence
of DOM due to the complexity of both molecular composition of DOM
and interactions between DOM and surrounding environments. In this
study, soil DOM samples were extracted from 33 soils collected from
different regions of China, and we investigated the effects of climate
and soil properties on the chemodiversity of DOM across different
regions of China, employing a combination of Fourier transform ion
cyclotron resonance mass spectrometry, optical spectroscopy, and statistical
analyses. Our results indicated that, despite the heterogeneity of
soil samples and complex influencing factors, aridity and clay can
account for the majority of the variations of DOM chemical composition.
The finding implied that DOM chemodiversity is an ecosystem property
closely related to the environment, and can be used in developing
large-scale soil biogeochemistry models for predicting C cycling in
soils.