More acidic seas could corrode teeth of sharks

Sharks are the most feared predators in the sea, and their survival hinges on fearsome teeth that regrow throughout their lives.

- BY PATRICK WHITTLE

But changes in the ocean’s chemistry could put those weapons at risk.

That is the takeaway from a study performed by a group of German scientists who tested the effects of a more acidic ocean on sharks’ teeth. Scientists have linked human activities including the burning of coal, oil and gas to the ongoing acidification of the ocean.

As oceans become more acidic, sharks’ teeth could become structurally weaker and more likely to break, the scientists found. That could change the big fish’s status at the top of the ocean's food chain, they wrote.

The ocean will not become populated with toothless sharks overnight, said the study’s lead author, Maximilian Baum, a marine biologist at Heinrich Heine University Duesseldorf. But the possibility of weaker teeth is a new hazard to sharks that already face pollution, overfishing, climate change and other threats, Baum said.

"We found there is a corrosion effect on sharks’ teeth," Baum said. "Their whole ecological success in the ocean as the rulers of other populations could be in danger."

Changes could come gradually

The researchers, who published their work in the journal Frontiers in Marine Science, performed their study as ocean acidification has become an increasing focus of conservation scientists.