Study uncovers mechanism for grassland carbon sink on Qinghai-Tibet Plateau

XINING, June 18 (Xinhua) -- A new study has unveiled the key mechanism for alpine grassland carbon sink on the Qinghai-Tibet Plateau in western China, providing scientific underpinning for ecological security.

The study, conducted by researchers from the Northwest Institute of Plateau Biology (NWIPB), under the Chinese Academy of Sciences, has been published in the journal Agricultural and Forest Meteorology.

The Qinghai-Tibet Plateau alpine ecosystem serves as a critical carbon sink, with its seasonal and interannual variation in carbon assimilation capacity regulated by climatic factors. It is of importance to enhance understanding of the carbon cycle mechanism in this region, said He Fuquan, a researcher at the NWIPB.

The research team collected cumulative observation data from 24 sites on the Qinghai-Tibet Plateau.

These sites are located in various environments of the alpine grassland ecosystem -- including alpine meadows, alpine wetlands, alpine shrub meadows, alpine steppes and tame grasslands.

Researchers analyzed interannual anomalies in seasonal and annual net ecosystem exchanges, carbon uptake periods, and the maximum rate of net carbon uptake in relation to climatic variables across various alpine ecosystems.

They found that alpine steppes exhibited the longest carbon uptake period but the lowest maximum rate of net carbon uptake, while tame grasslands had a shorter carbon uptake period than natural grasslands.

Spring precipitation is the key "trigger" which initiates the carbon uptake cycle in natural grasslands. In the growing season, meanwhile, the duration of the carbon uptake period is jointly determined by early-season precipitation and the grassland type, contributing to interannual variability and ecosystem differences in terms of net ecosystem exchange, the study revealed.

Looking ahead, the research team will focus on the impact mechanism of climate anomalies on the carbon uptake period and maximum rate of net carbon uptake, He explained.

Researchers will further improve the dynamic prediction model concerning alpine carbon sinks and provide enhanced support for ecological security, He added. ■