Ocean Acidification Can Cause Mass Extinction to Marine Life
Wed, April 21, 2021

Ocean Acidification Can Cause Mass Extinction to Marine Life

Over the past 200 years, the average ocean pH has dropped to 8.1 and will presumably drop by another 0.3 to 0.4 units by 2100. The oceans will then become 100 to 150 percent more acidic / Photo by: AvidExplorer via Pixabay

 

The Earth’s oceans have maintained a slightly alkaline state with an average pH of around 8.2  for millions and millions of years. But since the beginning of the Industrial Revolution, ocean acidity has increased by 30 percent, 100 times faster than any change in acidity experienced by marine organisms for at least the last 20 million years. This increase is due to humans burning fossil fuels and changing the way land is used.

Over the past 200 years, the average ocean pH has dropped to 8.1 and will presumably drop by another 0.3 to 0.4 units by 2100. The oceans will then become 100 to 150 percent more acidic. According to UNESCO, if this continues, the ocean will become corrosive to the shells of many marine organisms by the end of this century. It is unknown how marine life will adapt at this point. Ocean acidification will not only threaten the oceans and the species but also cause great impacts on tourism, food security, shoreline protection, and biodiversity.

A 2018 study conducted by scientists at the University of Tsukuba in Japan, the University of Plymouth in the UK, and the University of Palermo in Italy looked into how ocean acidification is damaging marine ecosystems. According to Phys.org, an internet news portal that provides the latest on science, the findings showed that ocean acidification chokes corals and lowers overall marine diversity. Although it will benefit a few plant species, smaller weeds and algae tend to blanket the seabed.

The researchers examined underwater CO2 gradients created by volcanic seeps where they recorded how flora and fauna responded to seawater acidification. They discovered far fewer corals and other calcified life, which means that there has been less biodiversity in those areas. “It shows the extensive damage caused by humans due to CO2 emissions over the past 300 years and unless we can get a grip on reducing CO2 emissions we will undoubtedly see major degradation of coastal systems worldwide,” Jason Hall-Spencer, Professor of Marine Biology at the University of Plymouth, said. 

What Happened 66 Million Years Ago

Past catastrophic events often give scientists a glimpse into what will happen on our planet. A massive asteroid millions of years ago can show us how marine ecosystems can potentially collapse. 

A massive asteroid struck Mexico about 66 million years ago, releasing billions of tons of sulfur into the atmosphere, triggering a mile-high tsunami, and sparking wildfires that stretched for hundreds of miles. The earthquake-driven gravity flowed and the ejection of molten rocks caused by the giant asteroid resulted in acid rain and large scale acidification of the world's oceans. It bore a hole nearly 100 miles wide into the seafloor and created a bubbling pit of molten rock and super-hot gas. 

All of the molten rocks and super-hot gas caused a mountain-high plume that poured acid rain into the oceans. This prompted a mass extinction of most marine and land-based life, including all dinosaurs. About 75 percent of life on Earth was erased during that time. A recent study published in the Proceedings of the National Academy of Sciences reported that the oceans suffered rapid and intense acidification. At the same time, the asteroid damaged marine food webs, sparking a mass extinction. "It's flash acidification, and it transformed ecosystems for millions of years," Noah Planavsky, one of the study's authors, said.

Past catastrophic events often give scientists a glimpse into what will happen on our planet. A massive asteroid millions of years ago can show us how marine ecosystems can potentially collapse / Photo by: Max Pixel

 

However, the mechanism by which marine species perished was unknown until today. According to CNN, an American news-based pay television channel, the researchers studied sea shells trapped in sediment which formed just after the asteroid hit. They also took samples from caves and rivers in Texas, Mississippi, and the Netherlands, and also from deep-sea drilling sites. 

The scientists discovered that there was an increase in the acidification of the seas over the 100 to 1,000 years after the asteroid impact, which caused the pH to drop by 0.25 units. They found that the walls of the fossilized shells also appeared "much thinner and poorly calcified after the impact."

If carbon emissions aren’t reduced by 2080, our oceans may become so acidic, even marine species like corals may erode faster than they can rebuild. Ocean acidification can cause the mass extinction of marine life again / Photo by: venriquez via Pixabay

 

Mass Extinction to Marine Life Can Happen Again

If carbon emissions aren’t reduced by 2080, our oceans may become so acidic, even marine species like corals may erode faster than they can rebuild. Ocean acidification can cause the mass extinction of marine life again. According to British newspaper The Guardian, the seas are again becoming more and more acidic due to the climate crisis. Humanity is at risk of a potential “ecological collapse” in the oceans as they absorb carbon emissions from the burning of coal, oil, and gas.

“We may think of [acidification] as something to worry about for our grandchildren. But if it truly does get to the same acidification as at the [meteorite strike] boundary, then you are talking about effects that will last for the lifetime of our species. It was hundreds of thousands of years before carbon cycling returned to normal,” lead author Michael Henehan of the GFZ German research center for geosciences in Potsdam said. 

Thus, it is important that the environmental issues we are facing today are solved as soon as possible. Governments must be responsible while corporations should be held accountable. If not, we will be experiencing a mass extinction not only of marine life, but life globally as well.