近日，加拿大不列颠哥伦比亚大学Sean A. Crowe团队研究了海洋缺氧时黄铁矿埋藏产生的碱性对气候的稳定作用。相关论文发表在2025年5月21日出版的《自然—地球科学》杂志上。
缺氧海洋环境中黄铁矿的形成和埋藏有助于调节海洋的酸碱平衡。尽管它具有潜在的重要性，但这种缺氧碱度产生对全球碳循环和地球长期气候调节的影响在很大程度上被忽视。研究组使用碳硫耦合循环模型，表明黄铁矿埋藏可以推动在整个显生宙产生5-46 Tmol yr−1的碱度，高达现代背景火山碳通量的六倍左右。
在广泛的海洋缺氧期间（称为海洋缺氧事件），通过黄铁矿埋藏产生的碱度被放大，因此成为气候系统的重要稳定机制，平衡了同期大型火成岩省火山活动的碳排放。该结果表明，在过去300 Myr中，大型火成岩省发生的几次最严重的海洋缺氧事件中，缺氧-碱度反馈被参与其中，因此在限制这些事件对生物圈和气候的总体影响方面发挥了作用。研究组得出结论，海洋脱氧可能对海洋-大气二氧化碳分配提供重要的负反馈，有助于缓冲二氧化碳排放对地球系统的影响。
附：英文原文
Title: Climate stabilization by alkalinity production from pyrite burial during oceanic anoxia
Author: Fakhraee, Mojtaba, Bauer, Kohen W., Planavsky, Noah J., Reinhard, Christopher T., Crowe, Sean A.
Issue&Volume: 2025-05-21
Abstract: Pyrite formation and burial in anoxic ocean environments helps to regulate the acid–base balance of the oceans. Despite its potential importance, the impact of this anoxic alkalinity production on the global carbon cycle and Earth’s long-term climate regulation has been largely overlooked. Here, using a coupled carbon–sulfur cycle model, we show that pyrite burial could drive 5–46Tmolyr1 of alkalinity production—up to about six times the modern background volcanic carbon flux—throughout the Phanerozoic eon. During periods of widespread oceanic anoxia (known as oceanic anoxic events), alkalinity production via pyrite burial is amplified and so becomes an important stabilizing mechanism for the climate system, counterbalancing carbon emissions from contemporaneous large igneous province volcanism. Our results indicate that the anoxia–alkalinity feedback was engaged during several of the most severe oceanic anoxic events from large igneous provinces during the past 300Myr, and thus played a role in limiting the overall impacts of these events on the biosphere and climate. We conclude that ocean deoxygenation may provide an important negative feedback on ocean–atmosphere CO2 partitioning, helping to buffer the impacts of CO2 emission on the Earth system.
DOI: 10.1038/s41561-025-01698-0
Source: https://www.nature.com/articles/s41561-025-01698-0