The ocean is full of surprises, and one of the most fascinating right now is an enormous iceberg named A23a, which is performing a slow, spinning-top routine in the Southern Ocean. This 3,600 sq km (1,400 sq mile) iceberg is caught in a phenomenon known as a Taylor Column, where ocean currents are diverted around an underwater bump, creating a rotating column of water that can trap objects like this iceberg for years.
Prof Mike Meredith from the British Antarctic Survey describes Taylor Columns as one of the “cutest” oceanic features, noting that they can form in both water and air, ranging from just a few centimeters in a lab setting to massive scales like this one in the Southern Ocean.
A23a’s extended dance is a perfect example of how the shape of the seafloor influences ocean behavior. Submarine mountains, canyons, and slopes play a crucial role in directing water movement, mixing, and nutrient distribution—factors that impact marine life and the global climate system by dispersing heat energy across the planet.
The area where A23a is spinning has been well-surveyed, revealing the underwater landscape that’s influencing its movements. However, this level of detailed mapping is rare, with only about a quarter of Earth’s seafloor mapped to modern standards. Understanding these underwater features is vital, as they hold the key to unlocking many of the ocean’s mysteries and their broader impact on our world.