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After the asteroid impact that wiped out the dinosaurs, part of the planet will fall into darkness
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Nationalgeographic.co.id—The years after the devastating asteroid impact dinosaur non-avians are dark times—literally. Soot from fire The raging forest filled the sky and blocked the sun, which directly contributed to the waves extinction that followed, according to new research.
After the asteroid hit Earth, about 66 million years ago, that natural disaster wiped out many life forms instantly. However, the impact also causes environmental changes that lead to extinction mass that takes place from time to time. One of the triggers extinction These are probably thick clouds of ash and particles that are spewed into the atmosphere and spread to the planet. As a result part Earth shrouded in darkness that can last up to two years.
During that time photosynthesis will fail, leading to the collapse of the ecosystem. And even after sunlight returns, this decline could persist for decades more, according to research presented December 16 at the annual meeting of the American Geophysical Union (AGU), held in New Orleans and online.
Richard Bizley
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Reconstruction of early primate life at the time of the mass extinction event 66 million years ago.
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The Cretaceous period (145 million to 66 million years ago) ended in an explosion when an asteroid traveling at about 27,000 mph (43,000 km/h) hit Earth. It is about 12 kilometers in diameter, and leaves a scar known as the Chicxulub crater, which is located underwater in the Gulf of Mexico near the Yucatán Peninsula and is at least 150 kilometers in diameter. The impact ended up wiping out at least 75% of the life in Earth, including all dinosaur non-avian (the lineage that gave rise to modern birds is the only branch of the family tree dinosaur survivors of extinction).
Clouds of crushed rock and sulfuric acid from the crash will darken skies, cool global temperatures, produce acid rain and trigger fire Forest. Scientists first proposed a post-asteroid “nuclear winter scenario” in the 1980s; This hypothesis suggests that darkness plays a role in extinction mass after the Cretaceous impact, said Peter Roopnarine, curator of geology in the Department of Zoology and Invertebrate Geology at the California Academy of Sciences, and presenter at the AGU meeting.
However, it’s only in the last decade or so that researchers have developed models that show how darkness can affect life, Roopnarine said. Live Science.
“The general thinking now is that global wildfires will be a major source of fine soot that will drift into the upper atmosphere,” Roopnarine said. “Soot concentrations in the first few days to weeks of fires will be high enough to reduce the amount of sunlight entering to a level low enough to prevent photosynthesis.”
Dark Time
Long-term darkness was studied by reconstructing the ecological community that would exist at that time from the asteroid impact. They used 300 known species from the Hell Creek Formation, a fossil-rich stretch of shale and sandstone dating from the late Cretaceous and extending into parts of Montana, North Dakota, South Dakota, and Wyoming.
“We focused on that region because the fossil record is well sampled and ecologically well understood, so we can reliably reconstruct the paleocommunity,” said Roopnarine.
They then created simulations that exposed their communities to periods of darkness lasting between 100 and 700 days, to see which intervals would have resulted in the vertebrate extinction rate preserved in the fossil record – about 73%, according to the presentation. The onset of post-impact darkness will be rapid, reaching a maximum in just a few weeks, Roopnarine said in an email.
The researchers found that ecosystems could recover after a period of darkness lasting up to 150 days. But after 200 days, the same community reached a tipping point, at which “some species became extinct and patterns of dominance shifted,” the scientists reported. In simulations where darkness lasts for its maximum duration, extinction spikes dramatically. During the 650 to 700 day darkness interval, the extinction rate was 65% to 81%, indicating that the Hell Creek community experienced about two years of darkness, according to the model.
Also Read: Scientists Investigate Second Largest Extinction in Earth’s History
“Conditions vary around the world due to atmospheric flow and temperature variations, but we estimate that darkness could persist in the Hell Creek area for up to two years,” said Roopnarine, adding that the findings were preliminary and
Once the ecosystem reaches its tipping point, it can finally recover with the distribution of new species; However, that process would take decades, the researchers found. Extended stimulation of the Hell Creek community going dark for 700 days suggests that once the darkness wears off, it can take 40 years for ecosystem conditions to begin to recover, scientists reported at the conference.
Also Read: What Happens When A Dinosaur-Destroying Asteroid Hits Earth?
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