Carbon dioxide emissions from human activities are altering the chemistry of oceans. As more CO2 is released into the atmosphere, a significant portion of it is absorbed by seawater. This reduces the ocean’s pH, driving greater acidity, and disrupts marine ecosystems – a process known as ocean acidification. The acidifying oceans pose problems for many organisms, including sharks.
Sharks are one of the top marine predators. Their teeth are their weapons. Razor-sharp and constantly replaced, their teeth are essential for their survival. But new research, recently published in the journal Frontiers in Marine Science, has found that sharks may lose their edge as the oceans become more acidic.
Scientists in Germany examined the teeth of Blacktip reef sharks under current and future ocean acidification scenarios. Today, the ocean’s average pH is about 8.1. By the year 2300, it could fall to 7.3, making seawater nearly ten times more acidic than it is now.
Shark teeth, though made of tough mineralized phosphate, are not immune to corrosion. The researchers incubated discarded shark teeth in tanks with different pH levels. After just eight weeks, the teeth exposed to more acidic water showed visible damage, including cracks, holes, weakened roots, and appeared structurally more fragile.
Since species like Blacktip reef sharks swim with mouths open to breathe, their teeth are constantly exposed to seawater and at continuous risk of damage.
Protecting ocean chemistry may be critical to protecting the top marine predators themselves.
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Photo, posted June 16, 2023, courtesy of Ryan Hagerty / USFWS via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
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