Stanford researchers concluded that a lack of oxygen in Earth's oceans led to the devastating extinction of various species some 444 million years ago.
The new results also indicate that these conditions (the oceans were virtually oxygen-free) lasted more than 3 million years – significantly longer than other biodiversity-destroying phenomena in our planet's history.
These findings are still relevant today: global climate change is contributing to a decrease in oxygen levels in the open ocean and coastal waters, a process that will sooner or later doom various animal species to extinction.
The research paper was published in Nature Communications on April 14 and focused on the event known as the Late Ordovician mass extinction. The event is recognized as one of the five greatest losses in the history of the Earth, the most famous of which is the Cretaceous-Paleogene event, which destroyed all dinosaurs about 65 million years ago.
Stanford scientists and their colleagues created a special model that allows you to limit the uncertainty about where in the seas of the Earth there was a lack of dissolved oxygen (so important for ocean life both then and now), as well as to what extent and for how long.
The model included previously published data on metal isotopes, as well as new data from black shale samples native to the Murzuk Basin in Libya that were recorded in geological records during the mass extinction.
Scientific work has led to the conclusion that in any reasonable scenario, the long-term lack of oxygen in the Earth's oceans has hit the ocean floor on a global scale. In this case, the event itself is associated with the so-called second impulse of mass extinction and it happened precisely in the late Ordovician period.
