Acidic
oceans implicated in Earth's worst mass extinction
Send a link to a friend
[April 13, 2015]
By Will Dunham
WASHINGTON (Reuters) - It is one of
science's enduring mysteries: what caused the worst mass extinction in
Earth's history. And, no, it is not the one that wiped out the
dinosaurs.
|
Scientists said on Thursday that huge amounts of carbon dioxide
spewed from colossal volcanic eruptions in Siberia may have turned
the world's oceans dangerously acidic 252 million years ago, helping
to drive a global environmental calamity that killed most land and
sea creatures.
The researchers studied rocks in the United Arab Emirates that were
on the seafloor at the time and contained a detailed record of the
changing ocean conditions at the end of the Permian Period.
"This is one of the few cases where we have been able to show that
an ocean acidification event happened in deep time," said University
of Edinburgh geoscientist Rachel Wood, one of the researchers in the
study published in the journal Science.
![](http://archives.lincolndailynews.com/2015/Apr/13/images/ads/current/Brandt_sda_101514.png) "This is significant because we believe our modern oceans are
becoming similarly acidic," Wood added. "These findings may help us
understand the threat posed to marine life by modern-day ocean
acidification."
Various hypotheses have been offered to explain the mass extinction
that exceeded even the one 65 million years ago caused by an
asteroid impact that erased the dinosaurs and many other animals.
The researchers said ocean acidification had long been suspected but
no direct evidence had been found until now.
Massive eruptions that formed an immense region of volcanic rock
called the Siberian Traps represented one of the largest volcanic
events of the past half billion years, lasting a million years and
spanning the boundary between the Permian and subsequent Triassic
Period.
[to top of second column] |
![](http://archives.lincolndailynews.com/2015/Apr/13/images/ads/current/grieme_lda_farm_2015.png)
The prodigious amounts of carbon dioxide from the eruptions had
awful consequences for land and marine life. The absorption of
carbon dioxide lethally, but temporarily, changed the chemical
composition of the oceans, the researchers said.
The mass extinction unfolded over a period of 60,000 years, they
said.
The horseshoe crab-like trilobites and the sea scorpions - denizens
of the seas for hundreds of millions of years - were among the many
marine creatures that vanished.
Land animals faced global warming and a general drying of the
climate. Most of the dominant mammal-like reptiles died, with the
exception of a few lineages including the ones that were the
ancestors of modern mammals including people.
The mass extinction also paved the way for the first dinosaurs about
20 million years later.
(Reporting by Will Dunham; Editing by Mohammad Zargham)
[© 2015 Thomson Reuters. All rights
reserved.]
Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
![](http://archives.lincolndailynews.com/2015/Apr/13/images/ads/current/farmers_bank_sda_prom_050614.png) |