Ocean chemistry and end-Permian mass extinction

Researchers report that the isotopic composition of sulfur (S) in Canadian and Japanese pyrite from Upper Permian-Lower Triassic ocean sediments is depleted in 33S and fluctuates between enriched and depleted 34S, and suggest that this isotopic pattern resulted from episodic mixing of deep, oxygen-poor, hydrogen sulfide-rich waters with shallow, oxygen-rich waters, potentially leading to the end-Permian mass extinction, marked by the disappearance of more than 80% of ocean species. - Read at PNAS.org

Article #16-10931: “Redox chemistry changes in the Panthalassic Ocean linked to the end-Permian mass extinction and delayed Early Triassic biotic recovery,” by Guijie Zhang et al.