How Ocean Acidification is Impacting Sharks’ Teeth: What You Need to Know

How is climate change affecting sharks, one of the ocean’s top predators? Recent research looked into the impacts on their unique teeth.

As carbon emissions rise, the ocean absorbs more CO₂, lowering pH levels and making the water more acidic. This change can harm many sea animals and ecosystems. Maximilian Baum, a biologist from Heinrich Heine University, shares that this study examines whether sharks’ teeth could also be at risk. Sharks that swim with their mouths open are constantly exposed to seawater, so their teeth might be vulnerable too.

Baum emphasizes, “Not just small creatures like corals are in danger; even apex predators like sharks show signs of damage from acidified waters.” His team collected 600 naturally shed teeth from blacktip reef sharks at a German aquarium. These sharks often lose and regrow their teeth, which can happen quickly—sometimes in just a few days.

In their experiment, the researchers placed 16 healthy teeth and 36 slightly damaged ones in separate tanks for eight weeks, with one tank maintaining normal pH levels and the other simulating more acidic conditions expected by 2300, according to a study from 2003.

Statistics from the National Oceanic and Atmospheric Administration reveal that since the industrial revolution, ocean acidity has risen by about 30%. The more acidic water caused visible damage to shark teeth, like cracks and corrosion, which could change how sharks eat. Sebastian Fraune, a professor at Heinrich Heine University, noted that this damage could affect feeding efficiency and increase energy needs, which is especially concerning for species with slower tooth replacement.

However, the study has some limitations. Ivan Nagelkerken, a marine ecology professor at the University of Adelaide, pointed out that the tests may not fully represent conditions in a living shark’s mouth. He emphasizes that their past study suggested sharks’ teeth might hold up better against acidification than this recent research indicates.

Despite its limitations, the current study adds important insights. Its goal was to illustrate the chemical effects of acidified seawater on shark teeth, a subject with limited existing data. Baum underscores that shark teeth are vital for their survival and ecosystem health. If ocean acidification weakens sharks alongside other factors like overfishing and plastic pollution, it could lead to significant changes in marine ecosystems.

This research sheds light on an important aspect of climate change. Understanding how it impacts apex predators can help us grasp the broader implications for ocean health and biodiversity.

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