20 years of "loyalty"! He and the Qinghai-Tibet Plateau "breathe together"

Wang Xiaodan (first from right) and his team members collected soil samples from vegetation roots in Mount Gongga. Photo courtesy of Chengdu Mountain Research Institute of Chinese Academy of Sciences

The Qinghai-Tibet Plateau is vast, vast enough for researchers to spend their entire lives trekking there. Wang Xiaodan, a researcher at the Chengdu Institute of Mountain Hazards and Environment of the Chinese Academy of Sciences (hereinafter referred to as the Chengdu Institute of Mountain Hazards and Environment), has been based here and has been engaged in research on the environment and ecology of the Qinghai-Tibet Plateau for more than 20 years.

In recent years, the accumulation and flow of carbon in multiple spheres have received widespread attention from academia. Especially in the current context of "dual carbon", it has become a fundamental and important issue in the process of formulating roadmaps and comprehensive plans.

The Qinghai-Tibet Plateau, known as the "Asian Water Tower", has unique glaciers, permafrost, lakes, rivers, alpine grasslands and subalpine forests that provide a place for studying carbon processes in terrestrial ecosystems. Wang Xiaodan follows the pulse of nature, "listens" to the breath of the Qinghai-Tibet Plateau, and records everything about carbon.

Is it a “source” or a “sink”?

The Qinghai-Tibet Plateau is the world's largest alpine permafrost area. Climate warming may lead to the release of a large amount of permafrost carbon, but the warm and humid climate changes can also promote the increase of plant carbon fixation, making the regional carbon source and sink balance state and trend uncertain.

In August this year, the Tibet Ecological Environment Innovation Team of the Chengdu Mountain Institute where Wang Xiaodan is located, jointly with other research institutes and universities, released major progress in the research on the current status and dynamics of carbon sources and sinks in the terrestrial ecosystems of the Qinghai-Tibet Plateau.

Research shows that the alpine ecosystem of the Qinghai-Tibet Plateau is generally an important carbon sink and will form a negative feedback to climate warming. In other words, under the influence of warming and humidification, the vegetation on the Qinghai-Tibet Plateau absorbs more carbon dioxide than the amount released by the permafrost.

"We have preliminarily given a definite answer as to whether the Qinghai-Tibet Plateau is a 'source' or a 'sink'." To get this answer, Wang Xiaodan and his team have visited the Qinghai-Tibet Plateau countless times to conduct monitoring, calculate carbon emissions, and conduct experiments.

"To explain the carbon inventory, mechanism and prediction clearly, we need not only to collect and organize data, but also to think about how to solve it."

Among them, monitoring is a basic work that must be sustained over a long period of time. The monitoring and investigation of carbon on the Qinghai-Tibet Plateau by the Chengdu Mountain Research Institute can actually be traced back to the 1980s, but at that time it was only a part of the entire Qinghai-Tibet Plateau ecological research.

Around 2000, Wang Xiaodan joined the Chengdu Mountain Institute and followed in the footsteps of his predecessors, devoting himself to this field. In the past five years, he has "concentrated his firepower" on carbon-related work.

In 2010, in order to better monitor the changes in carbon dioxide, Wang Xiaodan and his team began to build an alpine grassland and wetland observation experimental station and set up an ecological monitoring network in Shenzha, Tibet.

Over the past decade, a "network" has been gradually spread out: from Zoige in the east to Rutog County in the west, from Yadong in the south to Hoh Xil in the north, the number of monitoring stations has risen to 32, and the monitoring instruments transmit data at a frequency of 10 times per second. "It's like installing a stethoscope on the Qinghai-Tibet Plateau, and you can hear its breathing at any time," Wang Xiaodan described.

In order to clarify the issue of "sink" and "source", Wang Xiaodan integrated the data of other research teams based on more than ten years of monitoring data. "By gathering scattered data, the longer the time span and the wider the coverage, the more convincing the analysis results will be."

Enrich your understanding through twists and turns

In the field of scientific research, the understanding of things is constantly advancing, and the answers also have a "deadline".

"Although we have the support of so many years of historical data and have figured out the issues of 'sink' and 'source', there is still uncertainty in the future." Wang Xiaodan pointed out that there is still much uncertainty in the current model predictions about the future trend of carbon sinks on the Qinghai-Tibet Plateau.

"Under the influence of warming and humidification, when the temperature rises and the moisture increases to a certain level, whether there are risks and whether the trend has changed requires further verification."

This also means that the conclusions that have been drawn with great effort may need to be tested over a longer time scale. In Wang Xiaodan's view, this is the "helplessness" often encountered in scientific research. "Only by continuously obtaining data, developing methods and conducting analytical verification can our understanding advance in this process."

Wang Xiaodan's biggest "distress" comes from the "vastness" of the Qinghai-Tibet Plateau. "The large area and strong spatial differences in ecological types make me afraid that I will only see a single point or a local problem and find it difficult to grasp the whole." This is also the reason why he has been "sticking to one thing" in his research on the Qinghai-Tibet Plateau - he hopes to do more and see further.

Previously, a team invited Wang Xiaodan to do ecological research in other regions, but he declined. "I have always been on the Qinghai-Tibet Plateau. To do research in a field requires a foundation and accumulation."

In order to better listen to the "breathing" of the vast plateau, Wang Xiaodan dug deep into the ground to find out. "The biomass of the underground roots is a treasure trove. Because the temperature is low, the decomposition rate of soil organic matter is slow, so the carbon fixation capacity is strong." However, unlike remote sensing monitoring on the ground, the monitoring methods for underground are limited and mostly rely on digging.

Wang Xiaodan said that if it is just to calculate biomass, it is easy to operate, but to observe the changes in soil profile, in situ observation is necessary. At present, they use ground flux tower monitoring, underground soil profile moisture, temperature, gas synchronous monitoring and micro-root window root growth monitoring to form a three-dimensional monitoring system, so that underground ecological processes can be "captured" in real time.

“Breathing Together” with the Qinghai-Tibet Plateau

High-tech equipment provides support for scientific research, but sometimes the equipment that can be used normally in plain areas "strikes" for no reason when it comes to the plateau, which gives Wang Xiaodan and his team some headaches. "Maybe it's the weather, after all, the temperature here is too low, and sometimes we just don't know why. We can only try again and again and improve the equipment in a targeted manner to adapt to the plateau environment."

This is just a small episode in the scientific research work on the plateau. In Wang Xiaodan's view, the impact of natural conditions is objective, and all he can do is to overcome and adapt to it.

What's more important is to have a positive attitude. Sometimes due to altitude sickness, Wang Xiaodan couldn't sleep at night, and there were sometimes wild wolves wandering outside the tent. But as long as she could sleep for even an hour, she would be happy. "If you think about it this way, at least I slept for an hour, which is enough under these conditions."

The improvement of infrastructure on the Qinghai-Tibet Plateau has given Wang Xiaodan some optimism. "The roads are now open. It used to take three days to reach a place by crossing mountains and ridges, but now it only takes one day. It is more convenient to buy food and drinks along the way, and the conditions are much better." He witnessed the development here.

The persistence of his predecessors also influenced him. Once, Wang Xiaodan followed his teacher Zhong Xianghao to the Qinghai-Tibet Plateau to do a survey. Just after arriving in Lhasa, Zhong Xianghao, who was over 70 years old, suddenly fell ill and needed medical treatment urgently. "I advised him to go back to Chengdu for a check-up, since it was just finishing work, but the teacher insisted and returned only after the work was completed."

This is not the only "little thing" that deeply touched Wang Xiaodan. Previously, a student who worked in another city came back to Chengdu to visit Wang Xiaodan. During the chat, the student talked about his experience of doing a sample strip survey on the Qinghai-Tibet Plateau: driving all the way to an uninhabited area at an altitude of more than 4,000 meters, the altitude sickness was very serious, sitting in the pickup truck and vomiting, and had to go to the hospital for an infusion. When the doctor was about to use the needle to prick him, he burst into tears.

Although it was “light as a cloud” when recalling, and the students have already talked about this difficult period, there was one heartfelt statement that left a deep impression on Wang Xiaodan - “If you have persevered in such a tough environment, you will not be afraid of any difficulties in the future.”

Wang Xiaodan feels the same way. In his more than 20 years on the Qinghai-Tibet Plateau, he gained not only knowledge but also the tenacity to face life. He believes that the main reason he was able to persevere is because of his passion and interest.

"In addition, over time, I slowly integrated into this place, it became a habit, and I even developed feelings for it." While "listening" to the breathing of the Qinghai-Tibet Plateau, he gradually "breathes with" the Qinghai-Tibet Plateau.

China Science Daily (2021-12-30 Page 4, original title: "Listen! The Breathing Sound of the Qinghai-Tibet Plateau")

Author: Yang Chen

Editor | Zhao Lu

Typesetting | Zhihai