Climate change on Earth 50 million years ago left traces in shark teeth that researchers unearthed and analyzed
Shark teeth tell a story millions of years old and may be able to solve a mystery related to our planet’s climate. Tens of millions of years ago, in fact, tiger sharks hunted in the waters off the Antarctic Peninsula, right above a thriving marine ecosystem on the seafloor below. A University of California study, led by researcher Sora Kim, has shed light by explaining how our planet’s climate past and future are intertwined.
Mystery related to Earth’s climate solved by a shark tooth
Shark teeth may solve the mystery of why Earth, about 50 million years ago, began transitioning from a “greenhouse” climate, warmer than today, to colder conditions.
A now-extinct species of tiger shark once swam around the Antarctic Peninsula, and by analyzing the oxygen and other chemicals trapped in its teeth, researchers have found that it’s all down to the opening of the Drake Channel, which allowed the waters of the Pacific and Atlantic oceans to mix.
According to what has been confirmed by the data collected, in fact, the climate change would have started from Antarctica and in particular from the Drake Channel which would have formed a new current that could have completely overturned the world climate.
Higher-than-expected temperatures in the Drake Channel: the discovery
Important environmental information is encoded in the chemistry of each tooth and stored there for millions of years, and it showed that Antarctic waters, at least where sharks lived, were warmer than scientists had estimated.
Studying 400 tiger shark teeth from Seymour Island, the researchers found that the water temperature of the sharks back then was similar to that of the waters where modern sand tiger sharks are found today. In contrast, carbon dioxide concentrations were three to six times higher than they are today.
Despite these important discoveries about the origin of our planet’s climate, the researchers had to conclude that although the sand tiger shark once lived in higher temperatures than expected, the pace of global warming is now racing faster and faster, and this animal – as well as other living species – may no longer be able to adapt.
Armando Mercuri