近日，美国耶鲁大学Meng Guo课题组的一项最新研究发现在风化作用加速下，早期海洋pH值迅速上升。相关论文发表在2025年2月10日出版的《自然—地球科学》杂志上。

海洋pH值是调节地球系统演化各个方面的基本属性。然而，早期海洋pH值仍然存在争议，估计值从强酸性到碱性不等。

研究组开发了一个将全球碳循环与海洋地球化学、大陆生长与地幔热演化相结合的模型。通过将全球碳循环与海洋电荷平衡相结合，并利用地幔脱气和地壳演化的固体地球过程来描述挥发性分布和海洋化学的历史，结果表明，在冥古宙到太古宙早期，海洋pH值可能会迅速上升，pH值在大约4.0 Gyr前从5变为中性。

这种快速的pH值演变主要归因于冥古宙海底和大陆风化作用的加速。风化加速源于冥古宙地球动力学的独特特征，包括快速地壳形成、不同的地壳岩性和快速板块运动。约4.0 Gyr前，地球可能在冥古宙末期从不宜居状态转变为宜居状态，这对行星的宜居性和生命的起源具有重要意义。

附：英文原文

Title: Rapid rise of early ocean pH under elevated weathering rates

Author: Guo, Meng, Korenaga, Jun

Issue&Volume: 2025-02-10

Abstract: Ocean pH is a fundamental property regulating various aspects of Earth system evolution. However, early ocean pH remains controversial, with estimates ranging from strongly acidic to alkaline. Here we develop a model integrating global carbon cycling with ocean geochemistry, and incorporating continental growth and mantle thermal evolution. By coupling global carbon cycle with ocean charge balance, and by using solid Earth processes of mantle degassing and crustal evolution to specify the history of volatile distribution and ocean chemistry, we show that a rapid increase in ocean pH is likely during the Hadean to the early Archaean eons, with pH evolving from 5 to neutral by approximately 4.0 Gyr ago. This rapid pH evolution is attributed primarily to elevated rates of both seafloor and continental weathering during the Hadean. This acceleration in weathering rates originates in the unique aspects of Hadean geodynamics, including rapid crust formation, different crustal lithology and fast plate motion. Earth probably transformed from a hostile state to a habitable one by the end of the Hadean, approximately 4.0 Gyr ago, with important implications for planetary habitability and the origin of life.

DOI: 10.1038/s41561-025-01649-9

Source: https://www.nature.com/articles/s41561-025-01649-9