Waves Blamed For Earth's Largest Extinction

Posted: Feb 8 2017, 11:54am CST | by , Updated: Feb 8 2017, 12:00pm CST, in News | Latest Science News

 

Waves Blamed for Earth's Largest Extinction
Credit: Christine Daniloff
 

New evidence points to an uncharacteristic shoaling before and after great die-off 250 million years ago

About 250 million years, an extinction event wiped out almost all the life on Earth. It was considered the severe known mass extinction, with up to 96% of all marine species and 70% of terrestrial animals going extinct. Several theories have been put forward to explain the cause of this massive extinction but scientific community could not agree upon a single one. 

Prior researches have suggested that an unusually large amount of volcanic activity alongside multiple large asteroid impacts caused the planet to warm and also contributed to an increase in ocean acidification. The conditions were so harsh that most of the land and sea species went extinct. New research, however, provides another explanation for that major event.

In the latest effort, a team of international researchers examined rocks retrieved from Canada and China rocks that were once part of Panthalassic Ocean and found the evidence of an uncharacteristic shoaling before, during and after the great die-off.

The ancient rocks reveal clear evidence of sulphur oxide mixing with other types of sulphur. The radical change in ocean chemistry elevated the toxic levels to such an extent that it became nearly impossible for sea life to survive.

“To understand how most life on Earth went extinct 250 million years ago, we used multiple sulfur isotopes to investigate redox chemistry changes in the Panthalassic Ocean, comprising 85–90% of the contemporaneous global ocean. The S-isotopic anomalies from Canada and Japan provide evidence for the timing of the onset of euxinia and mixing of sulfidic and oxic waters.” Authors wrote in the study.

Researchers believe that the mixing in the oceans was likely caused by shoaling -  an increase in the wave amplitude that happens when water waves go from deep to shallow water,  particularly moving towards a shoreline. Since these waves come from a bottom of a body of water, they can significantly change dynamics of the oceans.

“This study illustrates how environmental changes could have had a devastating effect on Earth’s early biosphere, and may have present-day relevance because global warming and eutrophication are causing development of sulfidic zones on modern continental shelves, threatening indigenous marine life.” Study says.

Marine life took an extraordinary long time nearly 10 million years to recover from the extinction. Why recovery was so difficult and delayed, has also remained a mystery.

 

This story may contain affiliate links.

Comments

The Author


Hira Bashir covers daily affairs around the world.

 

 

Advertisement

comments powered by Disqus