Chinese scientists discovered supercritical carbon dioxide for the first time in nature
Xinhua News Agency, Qingdao, May 11 (Reporter Zhang Xudong) "Science Bulletin" recently published a research result of the Institute of Oceanology and Chinese Academy of Sciences' Ocean Research Center of the Chinese Academy of Sciences with a cover article: Chinese scientists are in a deep sea heat in the Western Pacific The discovery of supercritical carbon dioxide in the liquid area is the first time that supercritical carbon dioxide has been discovered in nature in the world, and provides new inspiration for studying the origin of life.
Zhang Xin, a researcher at the Institute of Oceanology, Chinese Academy of Sciences, introduced that during the 2016 deep-sea hydrothermal voyage of the "Science" scientific research ship, researchers used our own self-developed deep-sea in-situ Raman spectroscopy probes and found it in a 1400-meter deep-sea hydrothermal area. A hydrothermal vent that erupts containing supercritical carbon dioxide fluid.
"Under the conditions of 31 degrees Celsius and 7.3 MPa temperature and pressure, carbon dioxide exists in the form of supercritical state. Supercritical carbon dioxide has both gaseous and liquid properties and can quickly dissolve organic matter. Dry cleaning in daily life is used Supercritical carbon dioxide is also widely used in the petroleum industry as a solvent. Although it is widely used, it has never been found in nature before. "Zhang Xin said.
Using deep-sea in-situ Raman spectroscopy analysis, researchers found that the hydrothermal fluid containing supercritical carbon dioxide contains a large amount of nitrogen, which is much higher than the nitrogen concentration in the surrounding seawater and hydrothermal fluid, which shows that supercritical carbon dioxide has an enrichment effect on nitrogen . In addition, these hydrothermal fluids contain some unknown organic chemicals.
Scientists analyze and believe that the combination of supercritical carbon dioxide and nitrogen in the deep sea hydrothermal zone with surrounding minerals catalyzes the production of organic matter, thereby achieving the conversion process from inorganic to organic, and organic matter is the basis of life, which provides new inspiration for studying the origin of life on earth. .
Sun Weidong, a researcher at the Institute of Oceanology, Chinese Academy of Sciences, said that the biochemical community unique to hydrothermal fluids does not depend on sunlight and thermophilic characteristics. The deep-sea hydrothermal system is thought to be similar to the environment created by the initial life on Earth. The basic material of life is amino acids, but the key element of amino acids in the hydrothermal fluid is nitrogen, which is the most fatal problem of the early life originating from the hydrothermal hypothesis. The supercritical carbon dioxide fluid found in the deep-sea hydrothermal area is enriched with nitrogen in a large amount, which provides an excellent reaction medium for the early process of the earth from inorganic to organic.
Based on this research result, the research team proposed a new hypothesis for the origin of life on Earth: In the early period of the earth, the supercritical carbon dioxide layer existing at the interface between the ocean and the atmosphere was enriched with a large amount of nitrogen and combined with seawater and rock minerals that exposed the surface of the sea. Catalysis produces organic matter, becoming the source of early life on Earth.