Earth’s first mass extinction                                                 

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Context:

• A paper published in the journal, Nature Geoscience, has come up with a new reason behind the first mass extinction, also known as the Late Ordovician mass extinction.
• The article notes that the cooling climate likely changed the ocean circulation pattern.
• This caused a disruption in the flow of oxygen-rich water from the shallow seas to deeper oceans, leading to a mass extinction of marine creatures.

Ordovician mass extinction

The Ordovician mass extinction that occurred about 445 million years ago killed about 85% of all species. The other big extinction events were:

• The Devonian mass extinction (about 375 million years ago) wiped out about 75% of the world’s species.
• The Permian mass extinction(about 250 million years ago) also known as the Great Dying caused the extinction of over 95% of all species.
• The Triassic mass extinction (200 million years ago) eliminated about 80% of Earth’s species, including some dinosaurs.
• The paper concludes that climate cooling may have led to changes in nutrient cycling, primary producer communities which ultimately drove the Late Ordovician mass extinction.

https://indianexpress.com/article/explained/explained-earth-first-ordovician-mass-extinction-7611094/