Scientists studying the Permian extinction event, the greatest die-off in Earth’s history, when 90% of all life in the oceans went extinct roughly 250 million years ago (along with the extinction of two thirds of all land species), are finding troubling similarities to that crisis and the current mass extinction which is occurring in our lifetimes. Specifically, a new study shows that increased ocean acidification similar to whet we are seeing today, was one of the prime drivers of extinction during the Permian-Jurrasic boundary. From the abstract of the research paper published in Science:
Ocean acidification triggered by Siberian Trap volcanism was a possible kill mechanism for the Permo-Triassic Boundary mass extinction, but direct evidence for an acidification event is lacking. We present a high-resolution seawater pH record across this interval, using boron isotope data combined with a quantitative modeling approach. In the latest Permian, increased ocean alkalinity primed the Earth system with a low level of atmospheric CO2 and a high ocean buffering capacity. The first phase of extinction was coincident with a slow injection of carbon into the atmosphere, and ocean pH remained stable. During the second extinction pulse, however, a rapid and large injection of carbon caused an abrupt acidification event that drove the preferential loss of heavily calcified marine biota.
In laymen’s terms, increased absorption of carbon released from volcanic activity into the oceans led to an rapid increase in ocean acidification, much like we are observing today. The result? The mass die-off of ocean species:
The event, which took place 252 million years ago, wiped out more than 90 per cent of marine species and more than two-thirds of the animals living on land.
It happened when Earth’s oceans absorbed huge amounts of carbon dioxide from volcanic eruptions, researchers say.
This changed the chemical composition of the oceans – making them more acidic – with catastrophic consequences for life on Earth, the team says. […]
The findings are helping scientists understand the threat posed to marine life by modern-day ocean acidification. The amount of carbon added to the atmosphere that triggered the mass extinction was probably greater than today’s fossil fuel reserves, the team says.
However, the carbon was released at a rate similar to modern emissions. This fast rate of release was a critical factor driving ocean acidification, researchers say.
The Permian extinction event took place over a 60,000 year period. Our current extinction in the present, which scientists refer to as the Anthropocene, is 1000 times higher than rates of extinction before human beings appeared on the scene, or ten times worse than we previously believed. And clearly, ocean acidification is one of the largest drivers of extinction. We are already seeing an increase in “dead zones” in our oceans where life is virtually non-existent, and these dead zones are expected to expand as the temperatures continue to climb.
A full 94 percent of the dead zones in the world’s oceans lie in regions expected to warm at least 2 degrees Celsius by the century’s end according to a new report from the Smithsonian Tropical Research Institute and the Smithsonian Environmental Research Center published Nov. 10 in Global Change Biology. The paper states that warmer waters—mixed with other climate change factors—make for a dangerous cocktail that can expand dead zones.
Dead zones form in waters where oxygen plummets to levels too low for fish, crabs or other animals to survive. In deeper waters, dead zones may last for months, as with the annual summer dead zone in the Chesapeake Bay. Temporary dead zones may occur in shallow waters at night. The largest dead zones in the Gulf of Mexico and Baltic Sea can cover more than 20,000 square miles of the sea floor. The number of dead zones across the world is growing exponentially, doubling each decade since the 1960s.
“They’re having a big impact on life in the coastal zone worldwide,” said Keryn Gedan, a co-author and marine ecologist at the Smithsonian Environmental Research Center and the University of Maryland. “A lot of people live on the coast, and they’re experiencing more fish kills and more harmful algal blooms. These are effects of dead zones that have an impact on our lives.”
Combined with the effects of ocean acidification from the increase in carbon sequestration on our oceans and we have a recipe for an extinction event to rival if not surpass the one that ended Permian period.
Dr Matthew Clarkson, of the University of Edinburgh’s School of GeoSciences, who co-ordinated the study, said: “Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now. This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions.“
As many have noted, the current rise in the acidification of the earth’s oceans is occurring at an unprecedented rate:
The ocean is acidifying more rapidly than it has in
millions of years [HIGH CONFIDENCE]Today’s human-induced acidification is a unique event in the geological history of our planet due to its rapid rate of change.
An analysis of ocean acidification over the last 300 million years highlights the unprecedented rate of change of the current acidification. The most comparable event 55 million years ago was linked to mass extinctions of calcareous deep-sea organisms and significant changes to the surface ocean ecosystem. At that time, though the rate of change of ocean pH was rapid, it may have been 10 times slower than current change.
We are already seeing a die-off in marine species attributable to an increase in the acidity of our oceans, one directly linked to human use of fossil fuels.
Scientists already see ocean acidification harming marine animals like oysters, mussels and clams as well as coral reefs and floating marine snails called pteropods, dubbed the “potato chips of the sea” because of their significance to marine food webs. In the last decade, ocean acidification killed many oyster larvae at the Whisky Creek oyster hatchery in Oregon, shrunk the shells of pteropods in the Southern Ocean and slowed coral growth on Australia’s Great Barrier Reef. […]
The current rate of change in ocean conditions is simply too high for many marine animals to adapt, but to avoid further harm, society needs to create an even faster rate of change in energy supply options. If not, our planet risks losing the diversity and abundance of ocean life that we all depend on.
This new evidence about the role carbon absorption and ocean acidification played in the massive extinction that occurred at the end of the Permian should set off alarm bells all over the world, for we are facing a similar situation today. This time, however, it isn’t volcanic eruptions that are to blame, its humanity’s addiction to the burning of fossil fuels at a rate that is unsustainable for the existence of much of life on this planet.
