The secret to helping Antarctic scallops not freeze

Thanks to a special shell structure with many small ridges, Antarctic scallops can survive in extremely cold environments.

In Antarctica, objects and living things can freeze even when underwater. This is a big problem for sea travel in the polar regions.

The special structure of Antarctic scallop shells helps them avoid freezing.

Such supercooled water has temperatures just below freezing. Due to the high salt content, even though the freezing point is about -1.9 degrees Celsius, the water in Antarctica is about 0.05 degrees Celsius colder. Even the smallest disturbances such as grains of sand or fluctuating sea surfaces can also causes supercooled water to freeze, sometimes with deadly consequences for organisms that cannot survive in a frozen state.

However, Antarctic scallops (Adamussium colbecki) can survive in this environment, according to chemist Konrad Meister, a professor at the University of Alaska. During an expedition in Antarctica, Meister noticed Antarctic scallops with an effective anti-freeze mechanism.

"Our divers report that they have never seen large-scale ice forming on the surface of this native scallop," Meister said. New research published in the journal Communications Biology.

The international team, which includes members from the Max Planck Polymer Institute (MPI-P) and the University of Oregon, suggests that Antarctic scallops evolved a special surface structure during evolution to avoid frozen. While scallops in warmer regions have smooth or messy shell surfaces, the Antarctic species have a very "regular" structure.

Microscopic images show small ridges distributed in a radiating pattern from a central point on their shell. These ledges ensure that the water will first freeze there. If the freezing process continues, the ice will continuously accumulate and settle only on the ledges. Because of the low adhesion between the ice and the shell, weak currents can also wash away the ice, preventing the animal from freezing.

In addition to the microscopic studies, the team also conducted freezing experiments with Antarctic scallops and shellfish that live in warmer regions. They found that the force required to remove the ice from the Antarctic scallops was much less than that of the other species.

"It's exciting that evolution has given the Antarctic scallop an advantage. We could have new technological applications based on information about the crust that doesn't freeze. For example, surfaces that don't close up," he said. Ice can be very useful for polar transport," said Konrad Meister.