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Dinosaurs died under the same terrible conditions that plagued our oceans



There are some things that scientists know about the dinosaur-killing asteroid that struck Earth 66 million years ago. The impact point is the Chicxulub crater on the Mexican peninsula Yucatán. The asteroid in question was about six to nine miles wide and it was the beginning of the end for 75 percent of the world's plant and animal species at that time, including the dinosaurs.

A new study published in Proceedings of the National Academy of Sciences on Monday suggests that the asteroid not only led to mass extinction of dinosaurs and other species on land, but also to a massive extinction of the oceans and marine life. The results of the study, by Dr. med. Michael Henehan from the German Research Center for Geosciences (GFZ) and researchers from Yale University are the first direct evidence that the Cretaceous-Paleogene extinction was partly caused by a decline in the oceans. pH-values. This probably happened because the asteroid impact led to sulfur-rich rocks that caused acid rain that got into the ocean and disrupted its ecosystem.

Researchers sampled rocks from the Netherlands to analyze the chemical composition of fossilized foraminifera ̵

1; the small plankton that has an impressive fossil record dating back hundreds of millions of years – before, during, and after the asteroid strike. They measured Borisotope to understand the changes in the acidity of the ocean. Using Earth system models, they also reconstructed pH gradients of water columns and found that the proportions of borisotopes change as the acidity of the oceans increases. Since this shift took place in the first 100 to 1000 years after the asteroid impact in the great temporal context of the universe, it occurred almost instantaneously, which is why it was called a "lightning overdose event".

Their results reconcile competing theories of what caused the pH of the ocean to rise. For example, some researchers have suggested that volcanic eruptions occurred hundreds of thousands of years before the extinction of the Cretaceous and Paleogene, making the earth more prone to mass extinction. Instead, the evidence suggests that the influence of the asteroid caused the pH in the ocean to drop.

"Our data suggest that the influence and not volcanism contributed significantly to the extinction of the Cretaceous," said the authors in the study.

While acidification was predicted by other researchers, Noah Planavsky, a biogeochemist in Yale and one of the authors of the study, said in a salon interview that they were able to find an isotope signal as proof of true strength the impact of the impact.

"We knew this impact led to some acidification, but were surprised that this probably happened over such a short period of time," said Planavsky. "We had expected some acidification, but we did not know how big it would be and we were surprised to find it."

In other words, their results suggest that the asteroid that caused the extinction of the Chalk-Paleogene caused, more likely was catastrophic than previously thought.

"We knew there was an extinction, one of the most pronounced in the history of our planet, and the effects lasted millions of years. It was a short event that took millions of years, "said Planavsky.

What is alarming is that acidification is taking place in today's oceans on the planet, even without an asteroid that disturbs the environment due to carbon dioxide emissions. According to the National Oceanic and Atmospheric Administration (NOAA), the pH of the sea surface has fallen by 0.1 pH units over the past 200 years since the Industrial Revolution. According to NOAA, the oceans could be 150 percent more acidic by the end of the century based on the current carbon dioxide concentration, "resulting in a pH that the oceans have not experienced for more than 20 million years. "

Planavsky said the latest findings from the study give us some insight into what will happen in the future if carbon emissions continue to rise.

"Depending on what we do for carbon emissions, we could very easily have something more extreme than the signal we see," said Planavsky to Salon. "The level of acidification that we observe is certainly in line with what people are discussing over the next 100 years, and not only does it seem to have a short term impact, it also seems to have had an impact on marine ecosystems. The short-term event destabilized and changed the structure of ecosystems for millions of years, so this should be something we find terrible. It's in the range of something we could see in the future, but hopefully we will not see it that big. "


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