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Scientists may have discovered what caused one of the planet's worst extinctions




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Near the end of the Silurian era, 420 million years ago, nearly one quarter of life was wiped out in one of the planet's heaviest mass extinctions.

While some of the planet's most serious mass extinctions are strongly related to a single one destructive event (eg a meteor that caused the extinction of dinosaurs 65 million years ago), a special event known as the extinction of Lau / Kozlow kii ", a sustained geological event was a mystery because such a mechanism escaped the scientists. In a recent study, scientists may have finally figured out what caused this extinction.

About 100,000 years after the extinction of Lau / Kozlowskii, there was a sudden disruption of the Earth's carbon cycle that buried a tremendous amount of organic matter. Although the two events occurred in the immediate vicinity, it has proved difficult to link the extinction of Lau / Kozlowskii directly to the disruption of the carbon cycle, which has changed the climate and the environment.

To determine if such a link exists, the team rebuilt the oceanographic conditions of the Silurian Ocean using novel geochemical analysis methods that measured thallium and sulfur isotopes as well as manganese concentrations at sites in Latvia and Sweden. The authors found that, as with other mass mortality events, a rapid decline in ocean oxygen levels resulted in the extinction of deep-sea animals before animals found at shallower depths were also killed. The decrease in oxygen content was achieved by highly toxic marine conditions caused by sulphides in the water column. This rapid change in the Silurian Ocean has probably contributed to the disruption of the carbon cycle leading to extinction.

"This work provides further evidence that initial deoxygenation in ancient oceans coincides with the onset of extinction events," Dr. Jeremy Owens, a co-author of this study, "This is important as our observations of the modern ocean suggest that there is significant widespread deoxygenation, putting a heavier burden on organisms in need of oxygen and possibly the first steps towards further mass extinction in the ocean can. "

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via Getty Images. Years ago, nearly one quarter of life was erased by one of Earth's most serious mass extinctions

While some of the planet's most serious mass extinctions are strongly associated with a single destructive event (eg, a meteor causing dinosaur extinction 65 million years ago), this particular event has been described as the "extinction of dinosaurs." Lau / Kozlowskii ", a stubborn geological riddle has been increased, because such a mechanism has eluded scientists Researchers may have finally figured out what caused this extinction.

About 100,000 years after the extinction of Lau / Kozlowskii, there was a sudden disruption of the Earth's carbon cycle that buried a tremendous amount of organic matter. Although the two events occurred in close proximity, it proved difficult to directly associate the extinction of Lau / Kozlowskii with the disruption of the carbon cycle, which changed the climate and the environment.

To determine if such a link exists, the team rebuilt the oceanographic conditions of the Silurian Ocean using novel geochemical analysis methods that measured thallium and sulfur isotopes as well as manganese concentrations at sites in Latvia and Sweden. The authors found that, as with other mass mortality events, a rapid decline in ocean oxygen levels resulted in the extinction of deep-sea animals before animals found at shallower depths were also killed. The decrease in oxygen content was achieved by highly toxic marine conditions caused by sulphides in the water column. This rapid change in the Silurian Ocean has probably contributed to the disruption of the carbon cycle leading to extinction.

"This work provides further evidence that initial deoxygenation in ancient oceans coincides with the onset of extinction events," Dr. Jeremy Owens, a co-author of this study, "This is important because our observations of the modern ocean suggest that there is significant widespread deoxygenation, placing a greater burden on the oxygenated organisms and possibly the first steps towards further mass extinction in the sea can. "


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