A Series Of Extreme Environmental Crises Between 185 And 85 Million Years Ago Led To The Mass Extinction Of Marine Life And Changed The Course Of Evolution On Earth
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.
wiizii – stock.adobe.com – illustrative purposes only
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
Gernon and colleagues referred to the phenomenon as a “geological tag team.” They also discovered that the timing of the weathering pulses aligned with most oceanic anoxic events in the rock record.
They suggested that the phosphorus in the ocean served as a “natural fertilizer,” enhancing the growth of marine organisms.
However, the boost in biological activity also caused enormous amounts of organic matter to sink to the ocean floor, where it consumed large amounts of oxygen, according to study co-author Benjamin Mills, a professor of earth system evolution from the University of Leeds.
Eventually, the process caused large parts of the ocean to become anoxic or depleted of oxygen. This created “dead zones” where most marine life met their ends. The anoxic events lasted for about one to two million years.
Overall, the study shows how the Earth’s solid interior and surface environment and biosphere are more strongly connected than previously thought, especially during periods of tectonic and climactic catastrophes. It can also reveal how our planet may respond to similar stresses in the future.
The study was published in the journal Nature Geoscience.
Welcome to Billionaire Club Co LLC, your gateway to a brand-new social media experience! Sign up today and dive into over 10,000 fresh daily articles and videos curated just for your enjoyment. Enjoy the ad free experience, unlimited content interactions, and get that coveted blue check verification—all for just $1 a month!
Account Frozen
Your account is frozen. You can still view content but cannot interact with it.
Please go to your settings to update your account status.
Open Profile Settings