Between 185 and 85 million years ago, a series of extreme environmental crises took place in the oceans, severely harming the existing marine life and altering the course of evolution on Earth.
According to scientists, the crises are called oceanic anoxic events. They occurred when the dissolved oxygen in the oceans became critically depleted.
The new study was led by experts from the University of Southampton. They said the events led to major biological changes, including mass extinctions of marine species.
They collaborated with academics from the universities of Leeds, Bristol in the United Kingdom, Adelaide in Australia, Utrecht in the Netherlands, Waterloo in Canada and Yale in the United States.
"Oceanic anoxic events were like hitting the reset button on the planet's ecosystems. The challenge was understanding which geological forces hit the button," said Tom Gernon, the lead author of the study and a professor of earth science at the University of Southampton.
The researchers analyzed how ocean chemistry was impacted by plate tectonic forces during the Jurassic and Cretaceous periods, which is known as the Mesozoic era and the age of the dinosaurs. Remnants from this time can be found along the Jurassic Coast on the U.K.'s south coast and the cliffs of Whitby in Yorkshire and Eastbourne in East Sussex.
The research team also performed statistical analysis and utilized computer models to explore how the chemical cycles in the oceans would have responded to the breakup of the supercontinent Gondwana.
Sometime during the Mesozoic era, Gondwana, the giant landmass on which dinosaurs once roamed, broke up into multiple pieces. The supercontinent's breakup event resulted in intense volcanic activity all over the world. The volcanic activity significantly contributed to changing the course of the planet.
"As tectonic plates shifted and new seafloors formed, large amounts of phosphorus, a nutrient essential for life, were released from weathering volcanic rocks into the oceans. Crucially, we found evidence of multiple pulses of chemical weathering on both the seafloor and continents, which alternately disrupted the oceans," Gernon said.
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