Shark teeth are under threat. Credit: Mile Ribeiro, Pexels
Sharks, feared by many for their predatory personalities and sharp teeth, may be facing a surprising new threat.
A study published on August 27, 2025, in Frontiers in Marine Science found that rising ocean acidity, driven by human CO2 emissions, could corrode sharks’ teeth from root to crown, making them weaker and more brittle.
Ocean acidification is eroding sharks’ teeth
As more CO2 enters the atmosphere and dissolves into seawater, oceans become increasingly acidic. According to the Intergovernmental Panel on Climate Change (IPCC), the global ocean pH, now averaging 8.1, could fall to 7.3 by the year 2300 – almost 10 times more acidic than today.
To test the impact, researchers at Heinrich Heine University Düsseldorf incubated Blacktip reef shark teeth in aquariums set to current pH levels (8.2) and the extreme 2300 projection (7.3). After eight weeks, teeth exposed to the more acidic water showed clear signs of damage.
“We observed visible surface damage such as cracks and holes, increased root corrosion, and structural degradation,” said Prof. Sebastian Fraune, senior author of the study.
Shark teeth are made of highly mineralised phosphate, making them strong cutting tools. But the study revealed that even these “weapons” cannot withstand future acidification scenarios.
“Shark teeth, despite being composed of highly mineralized phosphates, are still vulnerable to corrosion under future ocean acidification scenarios,” said lead author Maximilian Baum. “They are highly developed weapons built for cutting flesh, not resisting ocean acid.”
The findings suggest that while sharks can replace their teeth throughout their lives, the extra energy needed to repair or grow new ones in harsher waters could weaken survival chances.
These changes could reduce sharks’ ability to capture prey effectively, disrupting their role as apex predators in marine ecosystems.
Sharks already face threats from overfishing and habitat destruction. If their teeth erode under future ocean conditions, it could have cascading effects across food webs. Apex predators help regulate populations of fish and other marine life; weakening them may destabilise entire ecosystems.
These findings add another layer of urgency to global efforts to reduce carbon emissions. If climate change can strip sharks of their teeth, the ripple effects could be felt across fisheries, coral reefs, and even human food security.
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