Flippers And Fins

It’s a hole! It’s a cave! Well, it’s a , so it’s kind of both! These large sinkholes formed as caves on land during the last ice age, when sea levels were hundreds of feet lower than today. Eventually the caves collapsed and filled with water as sea levels rose again.

For coastal geologist Jeff Donnelly (seen here with his team in a small boat taking core samples from the bottom of Thatchpoint Bluehole in the Bahamas), blue holes provide a perfect trap for sediments and debris left behind by hurricanes and cyclones, providing clues about the ancient climate.

Learn more! www.whoi.edu/oceanus/feature/blue-holes-and-hurricanes/

📸 Richard Sullivan, Texas A&M University at Galveston