Study: Scientists confirm that the largest mass extinction was linked to strange periodic bursts in oxygen levels

Fareeha Arshad
Photo by Matt Hardy on Unsplash

More than 250 million years ago, the world saw one of the largest mass extinction in history ever recorded, annihilating over 90% of the aquatic life forms and nearly 70% of vertebrates that survived on land. The extent of the life form destruction was so severe that it is also referred to as the ‘Great Dying’.

Though there are many mysteries behind this tragic event, there are a few speculations that scientists have put forward to explain the timescale and the reasons behind the mass extinction. In a recent study published in the journal Nature Geoscience, researchers have shed details on the environmental conditions before the event. In their extensive investigation, the scientists concluded a sudden increase in oxygen levels in the water bodies just before the mass extinction started.

Researchers believe that this sudden increase in oceanic oxygen levels happened sometime before the mass extinction period and continued for the next few centuries. Then, the oxygen levels started to drop again. They performed this study by analyzing thallium isotopes found deep inside the oceanic sediments to derive an idea of the oxygen levels in water bodies centuries ago.

The scientists have also recorded the opposite scenario: a decrease in the oxygen levels in water bodies – a condition called ocean anoxia. For example, during the Permian Triassic extinction period, there was a rapid decrease in the oxygen levels in oceanic bodies.

As for the mass extinction, scientists believe that a sudden increase in the carbon dioxide levels in the atmosphere owing to intense volcanic activity, especially in the Siberian region, must have been one of the reasons behind the Great Dying. With further studies on how the sudden oxygen levels in water bodies came about and its link with the mass extinction, scientists hope to better under the modern climatic changes we see today.

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I am a scientist by profession and a historian by passion. I write about current affairs, history, science, and lifestyle.

Texas State

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