There are signs in nature that herald the coming of a mass extinction. That was the case with the last one, which occurred 183 million years ago, and it could happen today. The sudden increase of CO2 in the oceans and the rapid decrease of some elements such as molybdenum are some of the events that occurred just before Earth. great extinction The penultimate from the Triassic-Jurassic was produced.
A massive increase in the concentration of carbon dioxide in the ocean, followed by a sharp decrease in trace elements crucial to marine life, preceded a mass extinction about 183 million years ago. – in the early Jurassic-. As a result, almost 90% of oceanic species and 75% of terrestrial species became extinct, succumbing to higher carbon concentrations than previously estimated.
Researchers who published their findings in the journal AGU Developments, measured the decrease in molybdenum concentration in the ocean. This element is a biologically important metal that dissolves in seawater. What they found was that before an extinction event, this micronutrient was reduced to residual levels due to a lack of oxygen in the system, not allowing it to carry out the reduction or oxidation reactions known as euxinic.
same thing now
However, the investigation was not left alone with the data showing that this metal was decreasing. “Our findings also help us understand how much carbon is circulating in the sea-atmospheric system, and the truth is, it was a much larger amount than previously thought,” said Jeremy Owens, one of the paper’s authors. This scientist added it is likely that these amounts of carbon will skyrocket “on a similar scale of modern atmospheric and oceanic increase due to human activities.”
And thisThere is an inversely proportional relationship between carbon and molybdenum.. Thus, when molybdenum was reduced to 41 gigatons, 244,000 gigatons of carbon dioxide were available in the ocean. Researchers analyzed rocks from three sites in Canada’s Alberta region. These were places that were part of the huge ocean that surrounded the ancient continent of Pangea.
Because the chosen location was connected to the global ocean in the past, the researchers were able to see at a single glance everything that happened in the global ocean 183 million years ago.
A decrease in molybdenum therefore means a large increase in organic carbon concentrations in the ocean, and moreover, it does so to a critical point where it becomes incompatible with life.
According to the calculations of this research group, the CO2 concentration in the ocean in this case was several times higher than previously predicted. These calculations are based on reference. carbon dioxide emitted by volcanoes around the world, Therefore, the researchers believe it should be reformulated to be more realistic.
The results of the research group showed that This reduction in molybdenum was what preceded the onset of an extinction one million years later. and that it took about two million years in total, much longer than scientists had previously estimated. While it is true that the planet’s conditions became more favorable for life after the extinction, the recovery process took hundreds of thousands of years.
The current climate change process has a lot to do with what happened 183 million years ago. As then, more and more CO2 is being added to the atmosphere and the system in general today, and we risk repeating the results.researchers point out.
as then the planet is currently facing a possible reduction in metallic micronutrients formed by the ocean, including molybdenum. Therefore, the risk of extinction due to global warming is more than a possible future scenario.
This is yet another indication that history is at great risk of repeating itself, with a sixth global extinction now, but in this case due to human action on the natural environment.
Reference work: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022AV000671
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