Amazing stuff!
Unfortunately, Stanford University could not resist demagoguery by drawing parallels to today's climate change:
"... Warming today
The Stanford researchers plan to examine more marine animal groups to further understand the intertwined impacts of the three stressors of warming, lack of oxygen, and acidification, which are growing in severity today.
The researchers emphasize that history could well repeat itself, as changing ocean conditions threaten modern species that are vulnerable to warmer, oxygen-depleted waters. ..."
Today's warming is hardly comparable to what went on in the during the Permian–Triassic extinction event.
"In brief
- The Permian–Triassic extinction event, which killed off most life on Earth, did not impact all animal groups equally.
- In the oceans, groups of animals collectively called the Paleozoic fauna that had long dominated marine environments were almost completely wiped out, but the so-called modern fauna experienced far fewer extinctions and have dominated since.
- New research reveals that the warmer, poorly oxygenated oceans of the Permian–Triassic transition strongly favored the modern fauna’s faster metabolisms, while the Paleozoic fauna’s slow metabolisms could not keep up with increased oxygen demand triggered by the warming waters.
...
About 252 million years ago, 96% of marine species and 70% of land animals died off during the Permian–Triassic extinction event ...
for the first time incorporates biological responses of the animal groups that were decimated in the extinction and those that fared better. The groups hit hardest were those whose metabolisms could least tolerate warm, poorly oxygenated water. Such conditions prevailed throughout much of the world’s oceans as the Great Dying unfolded, caused by a surge of volcanic activity that released gargantuan amounts of planet-warming gases like carbon dioxide and methane into the atmosphere. ..."
From the significance and abstract:
"Significance
The well-established faunal turnover event between the Paleozoic fauna (e.g., brachiopods, crinoids) and the Modern fauna (e.g., clams, snails, urchins) coincided with intense global climate change of the latest Permian. We hypothesize that physiological differences in species vulnerability to temperature-dependent hypoxia explains this ecological transition. We test this hypothesis by performing physiological experiments on different taxonomic groups, dramatically increasing the amount of physiological data available for understudied but ecologically significant marine taxa. Simulations of extinction patterns guided by these traits show that ocean warming and deoxygenation together caused the taxonomic selectivity of the end-Permian mass extinction and resulting permanent shift in marine ecosystem composition. Similar selectivity patterns are expected in the modern biodiversity crisis due to similar environmental circumstances.
Abstract
The rapid global climate change at the end of the Permian Period (~251.9 Mya) coincided with the greatest macroevolutionary faunal turnover event in Earth’s history.
As the oceans warmed, lost dissolved oxygen, and became more acidic, the dominant animal groups in the Paleozoic fauna (including brachiopods and crinoids) suffered differentially high rates of extinction, allowing the Modern fauna (including bivalves and gastropods) to rise to ecological dominance.
The end-Permian kill mechanism(s) are not fully understood, but differences in extinction intensity among Linnaean classes suggest an important physiological component.
Here, we use a trait-based model of species’ metabolic O2 balance to demonstrate that temperature-dependent hypoxia can explain the taxonomic selectivity of the end-Permian mass extinction.
Direct respirometry experiments and physiological trait estimates derived from biogeographic data reveal that species belonging to the Paleozoic fauna have a higher temperature dependence of hypoxia than those belonging to the Modern fauna. In simulations of the climate transition, this trait difference leads to a greater loss of aerobic habitat for Paleozoic fauna, consistent with their observed greater extinction intensity.
These results demonstrate that differences in average physiological tolerances to environmental change across biogeography, taxonomy, and functional ecology drove end-Permian extinction patterns and could eventually characterize the modern biodiversity crisis.
Temperature-dependent hypoxia is the only kill mechanism that has been shown to explain the magnitude, biogeography, and now taxonomic selectivity of the end-Permian mass extinction, ultimately underlying the permanent shift in marine ecosystems across this transition."
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