Are Sharks Facing Tooth Loss? Troubling Discoveries from German Biologists

Corals, shells and predators. The continuous increase in CO2 emissions since the 19th century has however transformed this balance. By absorbing almost a quarter of the carbon rejected into the atmosphere, the oceans have seen their pH fall at 8.1, which already corresponds to an increase in acidity of 30% compared to the pre -industrial era.

The intergovernmental group of experts on the evolution of the climate projects an even more marked acidification by the end of the century, with a pH around 7.8. Scientists believe that he could drop up to 7.3 by 2300. Behind these decimals hide major upheavals. Each fall of 0.1 unit reflects an increase of 25% of acidity.

Today, the acidification of the oceans attacks the teeth of the sharks

To measure the concrete impact of this chemical development, researchers from the Heinrich-Heine University of Düsseldorf have incubated black shark teeth in water simulating the pH provided in 2300. After eight weeks, the results published in Frontiers in Marine Science show a clear corrosion of roots and crowns, with the appearance of cracks and holes. The microstructures observed under the electron microscope reveal a rapid weakening, including in the most mineralized areas.

This vulnerability surprises because the shark teeth, mainly composed of fluorescent, are renowned for their resistance. However, permanent exposure to more acidic water accelerates their degradation. According to the study, this alteration concerns both the surface and the internal structure of the teeth, compromising their effectiveness in cutting the flesh of prey.

If sharks have the capacity to regenerate their teeth continuously, this mechanism could be put to the test. Producing and replacing teeth in a more corrosive environment represents an additional energy cost, reducing the energy available for growth, reproduction or hunting.

Tomorrow, compromised dentition and unbalanced oceans

The projections for the next two centuries suggest an ocean where predators would be weakened in their primary function. A shark with weakened dentition no longer has the same capture capacity or the same predation efficiency. In environments where competition is intense, this disadvantage can therefore prove fatal.

This loss would not be limited only to sharks. As a superpredateurs, they regulate the populations of many intermediate species. Their weakening could then upset the entire marine food chain. Herbivorous fish to corals, the whole ecosystem depends on this balance. If the teeth of the sharks become too vulnerable to fulfill their role, it is the health of the oceans that flicker.

Thus, the acidification of the oceans does not only destroy mineral microstructures. It erodes the power of predators that have shapes marine balance for millions of years, revealing a silent and lasting threat for the future of biodiversity.