青年说 ‖ 李依静：自然知道答案
Li Yijing, female, a master student from eco-environmental sciences of Chinese academy of sciences, Sino-Danish Center of university of CAS, focus on environment microbiology.
My name is Li Yijing, I’m a master student from research center for eco-environmental sciences, Chinese academy of sciences. Currently, my study interest is environment microbiology, I mainly focus on biodegradation of environmental pollutants. I’m very happy to share my learning experience in the field of environment subject, by the platform of “popular eco-youth talk”.
In my middle school age, I watched a documentary named Ocean by chance, and deeply touched by the splendor and vast of the underwater world. After that, I begun to seek more information on that, however, I gradually found that there are so many potential risks covered under the beauty of the deep blue—ocean acidification, plastic pollution, over-fishing, discharge of pollutants, so many issues have been threatening the biodiversity and eco-balance of ocean. The more I knew about eco-environment issues, the stronger the impulsion to do something became. Thus, firmly, I chose environment engineering as my first volunteer subject in college entrance examination. Until now, I still feel happy and proud for studying and working in this field, and I am even more determined to engage in this career.
Because I’ve been always interested in biology, so I chose environmental microbiology as my study interest at the beginning. From marine hydrothermal whose temperature can be as high as 400℃, to the whole year frozen plateau glacier, microorganism are ubiquitous in environment. Microbes are highly diverse in phylogeny with various genetic information, they perform a wide range of metabolism and growth patterns, and form microbial communities with distinct compositions and structures, and play unique roles in different niches in consequence. Even nowadays, when the microbial cultivation and identification technology has developed into a new stage, the microbes we can cultivate in the labs only accounts for 1~10% of the total microorganisms in nature, the hidden resources of microorganisms are still there for further explorations.
In my bachelor period, I mainly studied on anaerobic ammonium oxidation. The bacteria (anaerobic ammonium oxidation bacteria, AAOB) proceeding this process is magical, they choose a harsh way to make livings, namely, using nitrate/nitrite to oxidize ammonium under anoxic condition, and grow on inorganic carbonate as carbon source, thus the doubling time of AAOB can be as long as two weeks. However, living such a struggling life, AAOB contribute to half nitrogen removal in marine environment, as well as shed the light on the energy-efficient technology of anaerobic wastewater denitrogenation, which is a milestone discovery in the field of environmental microbiology.
In my master period, I mainly focus on anaerobic biodegradation of environmental organic pollutants. With the development of technology, various organic compounds have been released into environment, such as polycyclic aromatic hydrocarbon, herbicides, antibiotics, which results in risks to human health and eco-environment safety, due to their toxicity. It has been widely reported that, the newly synthesized compounds could cause severe inhibition on local bacteria when they enter certain environment at the beginning, because there may be lack of relevant degraders due to their complicated and specific molecular structure. However, through the natural evolution of indigenous microbes, several weeks or thousand years, the “enemy” of this pollutant would appear, maybe a certain species who evolved and harbor the specific degrading genes targeted on this certain compound, may be multiple populations working in synergistic pattern as well. In the process of industrialization, due to the delay characteristic of environment problem, human beings have created countless compounds that even ourselves have no idea about how to deal with, but luckily, it seems that nature always prepare an answer for that, in silence, waiting for the discovery of human beings. That is the mission for environmental microbiologist, in my mind, to find out those hidden answers.
Environment protection requires the combination of theory and practice, so I always cherish every opportunities of internship, and try to improve myself from practice experiences. By practice, I learn environmental knowledge both in depth and width. In my freshman year, I worked as a volunteer commentator in Green Hunan, the environment protecting NGO of Hunan province. I guided a group of children to visit Xiangjiang river, the mother river of Changsha city, and shared the knowledge about the test of water quality. The curiosity and deep concern on water resource protection shown by those children impressed me a lot, making me feel the responsibility of working as an environment protector. In my junior year, me and my classmates got the internship chance in large smelting companies, during that period, we went down to every workshop to learn the operating mechanism, the production of various pollutants in every unit and its relevant pollutant control strategies. Being personally on the scene, I obtained a deeper understanding on the pollutants production and control during the whole life cycle, and higher acknowledgement on the necessity of transformation to the clean production. When I studied in SDC of UCAS, under the guidance of professor Erik Jeppesen and Liu Zhengwen, I had an excursion to Taihu Lake, by combining the physiochemical water quality index with plankton and fish data over several years, I had deeper understanding on the eutrophication problem of Taihu.
Environment protection requires not only the update of technology and management, but also that everyone’s willingness to live a sustainable life despite the inconvenience may accompany.