Beijing, March 3 (Zhongxin Net) -- Soil is the largest active carbon reservoir in terrestrial ecosystems, and understanding soil organic carbon turnover (i.e. degradation) and its response to climate warming is crucial for accurately predicting future climate change.

According to the latest news from the Institute of Botany of the Chinese Academy of Sciences (Institute of Botany, Chinese Academy of Sciences), based on 3000 soil profiles spanning more than 13,<> kilometers in the grassland transect of the Qinghai-Tibet Plateau in China, Feng Xiaojuan's research group and Chinese and foreign collaborators have successfully revealed the turnaround time and temperature sensitivity of the main molecular components of soil organic carbon, including lignin, lipids and black carbon, by using advanced monomer compound radiocarbon isotope (C<>) analysis technology.

This study found that the turnover time of plant lipids and black carbon in the soil profile can reach tens of thousands of years, which is significantly longer than lignin. The turnover of plant lipids and black carbon is mainly affected by soil minerals and is not sensitive to temperature changes, while the turnover of lignin is mainly regulated by temperature and has high temperature sensitivity. By further integrating and analyzing the carbon 14 data of soil carbon components (light components and mineral binding components) around the world, the research team proved that mineral protection has an important regulatory effect on soil carbon turnover and temperature sensitivity.

This important progress in the research of soil organic carbon in relation to global climate change was completed by researcher Feng Xiaojuan and assistant researcher Jia Juan of the Institute of Botany of the Chinese Academy of Sciences, together with Chinese and foreign counterparts such as Lanzhou University, Peking University, Ocean University of China, Northwest Institute of Plateau Biology of the Chinese Academy of Sciences, ETH Zurich, Max Planck Institute in Germany, etc.

Feng Xiaojuan pointed out that the composition of soil organic carbon is complex, the chemical structure and environmental behavior of different molecular components (such as interaction with soil minerals) are very different, and their turnover and response to warming are also different. The traditional concept that lignin with aromatic ring structure is more difficult to degrade and rotates more slowly, while the new concept believes that environmental factors rather than chemical structure determine the turnover rate of soil organic carbon components, but there was no direct evidence before.

She said that the latest research results not only provide direct evidence for the instability of lignin in mineral soils, but also provide a reliable basis for the modification of soil carbon pool model parameters, and indicate that future climate warming may accelerate the degradation of lignin. Therefore, global warming may accelerate litter and degradation of lignin in soil, and forest and wetland soils with higher lignin content should receive more attention. (End)