南方科技大学Wang Dunfan及其课题组成员报道了，南极冰川形成期间太平洋呼吸碳储存增强的细菌磁化石证据。这一研究成果发表在2024年4月26日出版的国际学术期刊《地质学》上。

据介绍，随着南极冰期的开始全球变冷。始新世—渐新世过渡期(EOT)的34Ma结束了新生代早期温室气候状态，标志着冰室的开始。尽管pCO₂下降被认为是这种气候变化的一个主要原因，但人们对相关的碳固存机制仍不了解。

研究使用数值模拟结合了一种新的代用物——细菌磁化石，评估了整个EOT的海洋生产量和环流变化。细菌磁化石的丰度和形态对沉积有机质的积累和氧化作用非常敏感。研究发现赤道太平洋生物产量和氧化作用下降的同时，南大洋在EOT后生物产量增加。

模拟结果和来自亚南极地区的证据相一致，研究将这种违反直觉的组合解释为，由于南极冰川在EOT上的堆积而增强的南大洋底水形成和生物泵效率的结果。这些结果扩大了整个EOT的二氧化碳下降，并为太平洋深层缺氧和呼吸碳浓度的增加提供了关键证据。

附：英文原文

Title: Bacterial magnetofossil evidence for enhanced Pacific Ocean respired carbon storage during buildup of Antarctic glaciation

Author: Dunfan Wang, Yihui Chen, Yan Liu, Andrew P. Roberts, Eelco J. Rohling, Xiangyu Zhao, Xu Zhang, Jinhua Li, Weiqi Yao, Xuejiao Qu, Xianfeng Tan, Qingsong Liu

Issue&Volume: 2024-04-26

Abstract: Global cooling with the onset of Antarctic glaciation ca. 34 Ma across the Eocene–Oligocene transition (EOT) terminated the early Cenozoic greenhouse climate state and marked the beginning of icehouse conditions. Although a pCO₂ decline is considered to have been a major cause of this climate shift, the associated carbon-sequestration mechanism remains unclear. Here, we assessed ocean production and circulation changes across the EOT using numerical simulations combined with a novel proxy, namely, bacterial magnetofossils, the abundance and morphology of which are sensitive to sedimentary organic matter accumulation and oxygenation. We detected production and oxygenation declines in the equatorial Pacific Ocean coeval with increased biological production in the Southern Ocean after the EOT. Corroborated by simulation results and evidence from the Subantarctic region, we interpret this counterintuitive combination as a result of enhanced bottom-water formation and biological pump efficiency in the Southern Ocean due to Antarctic glacial buildup across the EOT. These results provide key evidence for deep Pacific Ocean deoxygenation and increased respired carbon concentrations, which amplified CO₂ decline across the EOT.

DOI: 10.1130/G52016.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52016.1/638900/Bacterial-magnetofossil-evidence-for-enhancedredirectedFrom=fulltext