A team from the California Academy of Sciences found the cause of the apocalypse after the earth was hit by an asteroid that destroyed the dinosaurs at a speed of 43,452 kilometers per hour. In a new study, the US team found that the main trigger for the extinction may have been clouds of ash and soot particles that spread through the atmosphere. These clouds last up to two years, putting much of the earth in darkness and making it difficult for anything to grow or survive. Life in the area surrounding the impact will be killed instantly, but there is significant more damage in the years following the collision. This includes tidal waves , floods and massive environmental changes, including the dispersal of small particles into the atmosphere that spread throughout the world. While the earth is shrouded in darkness, plants also fail to grow due to lack of sunlight to carry out photosynthesis. "This nuclear winter scenario, as first proposed in the 1980s, played a major role in the mass extinction," explains Peter Roopnarine, study author.
Roopnarine said the general thinking now was that global wildfires would be a major source of fine soot that would drift into the upper atmosphere. "Soot concentrations in the first few days to weeks of fires are high enough to block sunlight to prevent photosynthesis," he said.
The fossil record shows that about 73 percent of vertebrate species became extinct after the collision. Roopnarine said the impact of darkness would occur quickly, reaching a maximum within a few weeks. Most ecosystems can recover if darkness lasts only 150 days, but after 200 days they reach a 'tipping point'. This is the point at which some species become extinct and dominance among the remaining species shifts in a way that destroys ecosystems. When darkness lasted for up to 700 days later extinctions spiked dramatically - reaching up to 81 percent of all life, suggesting that animals in the Hell Creek community experienced about two years of darkness.
"Conditions vary around the world due to atmospheric flow and temperature variations, but we expect darkness to persist in the Hell Creek area for up to two years," Roopnarine said.
Further simulations of the Hell Creek community found that if it was dark for 700 days, it would take 40 years for conditions to recover. The findings were presented at the annual meeting of the American Geophysical Union. About 66 million years ago the non-avian dinosaurs were wiped out and more than half of the world's species were wiped out. The asteroid Chicxulub is often cited as a potential cause of the Cretaceous-Paleogene extinction event. It crashed into the shallows of what is now the Gulf of Mexico.The collision released a massive dust and soot cloud that triggered global climate change, wiping out 75 percent of all animal and plant species. Experts explain that loss of light from the sun causes a complete collapse in aquatic systems. This is because phytoplankton which is the basis of all food chains in dead waters.
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