Ocean acidification and its impacts

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Imagine you could see the impact of ocean acidification on marine life. There's a simple experiment you can try at home. Grab a seashell from your last beach trip, buy a fizzy drink, and put the seashell in the drink. Observe it after a few days. You'll notice the seashell dissolving gradually, illustrating the effects of ocean acidification.

What is ocean acidification?

Ocean acidification is the process by which carbon dioxide in the atmosphere is absorbed by the ocean, reacts with the seawater, and forms carbonic acid. Colder waters absorb carbon dioxide more quickly, making the Arctic Ocean particularly vulnerable to acidification. As carbon dioxide levels increase, hydrogen ions accumulate, causing the ocean's pH level to drop and making it more acidic.

Buffering and ocean pH

The ocean's pH is regulated by a process called buffering, where hydrogen ions react with calcium carbonate. While buffering can mitigate the effects of ocean acidification, it occurs over thousands of years, and at a rate too slow to counteract current increases in carbon dioxide levels. Since the Industrial Revolution, the pH level has already dropped by 0.1, a seemingly small amount, but representing a 30 per cent increase in acidicity, and large enough to negatively affect marine life.

The Arctic as a bellwether

The Arctic serves as an indicator of global ocean acidification, with the effects happening faster there than elsewhere. Prof Helen Findlay, a Biological Oceanographer from Plymouth Marine Laboratory, explains that organisms like copepods collected in the Arctic Ocean are being studied to see how they respond to predicted future pH levels.

Impact on marine life

Acidification affects marine organisms that have calcium carbonate shells or structures, which can affected as pH levels decrease. These organisms struggle to maintain their shells and could face severe consequences, with a cascading effect on larger fish and mammals that depend on them for food. Dr Ceri Lewis, from the University of Exeter, emphasizes that within a few decades, increased ocean acidity could become corrosive to smaller marine creatures, which are crucial to marine ecosystems.

Pterapod shell dissolved in seawater NOAA 800px NOAA
In laboratory experiments, this pterapod shell dissolved over the course of 45 days in seawater adjusted to an ocean chemistry projected for the year 2100.

By understanding ocean acidification and its impact on marine life, we can raise awareness and explore potential solutions to mitigate its effects. Just as the seashell dissolved in the fizzy drink, ocean acidification is starting to affect the survival of a range of species. It's crucial to address this pressing issue before it's too late.


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