Chengdu, June 6 (ZXS) -- The reporter learned from Chengdu University of Technology on June 1 that Professor Li Chao's research team at the International Research Center for Sedimentology and Biogeochemistry of the university used carbonate-bound phosphate (CAP) technology, which can directly track the phosphorus content of the ancient ocean, to reconstruct the fluctuation of dissolved phosphorus content in the ancient ocean during the geological critical period of the Edikala period (between about 6 million and 1 million years ago). It was found that there is a decoupling relationship between phosphorus content and ocean oxidation degree of marine life in the Ediacaran period, which is different from that of modern oceans, and the hypothesis that external factors are the original driving force for oxidation of the Ediacaran oceans and even the oxygen-deficient oceans of the early earth was proposed.

This achievement reveals the fundamental reason for the long hypoxic state of the Precambrian ocean, which accounts for more than 80% of the earth's history, and the fundamental mechanism of the eventual oxidation of the early Earth's hypoxic ocean, which greatly deepens the human understanding of the evolution of the earth's habitability. In the early morning of June 6, Beijing time, the article was published online in the international authoritative academic journal "Nature" with the title of "Deciphering the Edikala Phosphorus Cycle".

It is understood that many studies have shown that the Precambrian ocean is largely dominated by hypoxia stratification, and oxidation may only exist in areas such as shallow waters on the surface of the ocean. However, due to the lack of quantitative indicators that can directly track the dissolved phosphorus content in the ancient ocean, it is impossible to accurately quantify the temporal and spatial fluctuations of dissolved phosphorus in the ancient ocean.

In 2021, Professor Li Chao's team developed a CAP technology index that can directly track the phosphorus content of ancient oceans. The successful development of CAP technical indicators provides the possibility to answer the above major scientific questions.

With the help of researchers in China, Australia and the United States, Professor Li Chao's team collected typical Edikala geological profile samples from six different regions of four different ancient continents in China, Australia, the United States and Mexico, and analyzed the corresponding CAP records. These profiles and samples document an important oxidation event in the early Earth's oceans. The results show that the change of phosphorus content in the ancient ocean at that time was decoupled from the degree of oxidation of the ocean, which is completely different from the phosphorus-oxygen cycle coupling relationship in the oxidized ocean of the Phanerozoic.

Professor Li Chao said that the decoupling or extremely weak coupling relationship of phosphorus-oxygen cycle observed in the early ocean is likely to exist throughout the Precambrian, and this mechanism will lock the Precambrian marine system in a long-term stable hypoxia state, and the oxidation of the ocean needs to be driven by factors outside the ocean to achieve, which explains why the long Precambrian can always be stable in the main hypoxic state, and the complex life that depends on oxygen survival will go through the long Precambrian. It was only 5 million years ago that the Phanerozoic had a major explosion. (End)