远古海洋比想象中更“透气”！新研究刷新对全球海洋钼循环认知

Core Insights - A recent study by Chinese scientists reveals the critical role of deep-sea oxidative sediments in the global molybdenum cycle, enhancing the accuracy of geochemical indicators used to infer historical environmental changes on Earth [1][2] - The research, published in the journal Nature Communications, provides new scientific evidence for understanding the evolution of Earth's habitability and addressing future environmental changes [1] Group 1: Research Findings - The study indicates that the δ⁹⁸Mo values in deep-sea sediments are significantly higher than those in typical iron-manganese crusts and nodules, suggesting a global universality of this phenomenon [2] - A vertical increase in molybdenum isotope composition with depth was observed, driven by the penetration of molybdenum from bottom seawater into sediments and a recycling process within sediment columns [2] - The research team recalculated the output flux and isotopic composition of molybdenum from global oxidative sediments, finding that the flux is over twice previous estimates, accounting for 45% of the total oceanic molybdenum output [2] Group 2: Implications for Earth's History - The updated model suggests that previous studies may have significantly overestimated the distribution of "sulfidic anoxic" basins in the global ocean during geological periods such as the Paleoproterozoic, Cambrian, Early Jurassic, and the Permian-Triassic boundary [2] - This implies that ancient oceans may have been more "breathable" than previously thought, creating a more favorable environment for the evolution and flourishing of early life [3] - The changes in Earth's oxygen levels directly influenced the evolution of life and major biological events, such as the Cambrian explosion, providing key insights into the origins of life [3]