Ocean acidification and the Permo-Triassic mass extinction.

• Main Authors: Clarkson, MO, Kasemann, SA, Wood, RA, Lenton, TM, Daines, SJ, Richoz, S, Ohnemueller, F, Meixner, A, Poulton, SW, Tipper, ET
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Association for the Advancement of Science (AAAS) 2015
• Subjects: Animals; Aquatic Organisms; Atmosphere; Boron; Carbon; Carbon Cycle; Carbon Isotopes; Ecosystem; Extinction; Biological; Hydrogen-Ion Concentration; Isotopes; Oceans and Seas; Seawater; Time; Ocean acidification
• Online Access: https://www.repository.cam.ac.uk/handle/1810/293466; https://doi.org/10.17863/CAM.40611

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.