Stanford researchers led by Jose Andres Marquez, working under senior author Erik Anders Sperling, have confirmed why the Permian-Triassic extinction 252 million years ago killed off ancient seafloor life like brachiopods and sea lilies while sparing faster-metabolizing mollusks, fish and echinoderms. The study, published July 6 in Proceedings of the National Academy of Sciences, is the first to factor in the biological metabolism of the affected animal groups.
The "Great Dying" wiped out 96% of marine species and 70% of land animals after a surge of volcanic activity pushed ocean temperatures up 8-12°C over thousands of years and drained oxygen from the water. Slow-metabolizing filter feeders like brachiopods could not cope with the heat and low oxygen; only about 400 brachiopod species remain today, compared with 10,000-15,000 modern bivalve species descended from the extinction's survivors.
Sperling said the biggest mass extinction of all time started from a world very similar to today's. Current warming projections of 1.5-4°C by 2100 are far below the Great Dying's 8-12°C increase, but the study suggests even smaller shifts could strain marine life with similar metabolic vulnerabilities.