Stable isotopes and element concentrations of samples from the Wadi Bih, United Arab Emirates

Ocean acidification triggered by Siberian Trap volcanism was a possible kill mechanism for the Permo-Triassic Boundary mass extinction, but direct evidence for an acidification event is lacking. We present a high-resolution seawater pH record across this interval, using boron isotope data combined with a quantitative modeling approach. In the latest Permian, increased ocean alkalinity primed the Earth system with a low level of atmospheric CO2 and a high ocean buffering capacity. The first phase of extinction was coincident with a slow injection of carbon into the atmosphere, and ocean pH remained stable. During the second extinction pulse, however, a rapid and large injection of carbon caused an abrupt acidification event that drove the preferential loss of heavily calcified marine biota.

西伯利亚暗色岩（Siberian Trap）火山活动引发的海洋酸化，曾被视作二叠纪-三叠纪之交集群灭绝的潜在致死机制，但目前仍缺乏该酸化事件的直接实证。本研究依托硼同位素数据结合定量建模方法，重建了该地质时段内的高分辨率海水pH记录序列。二叠纪末期，海洋碱度升高使得地球系统处于大气CO₂浓度偏低、海洋缓冲能力较强的状态。灭绝事件的第一阶段与大气碳库缓慢注入过程同步发生，海水pH始终维持稳定。然而在第二次灭绝脉冲事件期间，碳组分快速且大规模的注入引发了突发性海洋酸化事件，进而导致钙化程度较高的海洋生物类群发生选择性消亡。