How to erase a ship—Arctic researchers work to eliminate their vessel’s fingerprints

Even locked in the ice, the Polarstern produces light, noise, and emissions that could affect many studies.

ABOARD THE POLARSTERN IN THE ARCTIC OCEAN—The flare cut through the sky like a firework, sending the polar bears into a panic. They sprinted across the snow, the mom checking to make sure her cub kept pace. Nearby, two polar bear guards—one who had fired the flare and the other armed with a rifle—stood on snowmobiles, making sure the bears posed no threat to the scientists and crew onboard this German icebreaker, which is spending 1 year here in the Arctic, frozen into the sea ice.

The bears are an occasional threat to this unusual expedition, known as the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC). But the scientists are also contending with another, much larger intruder: their own ship. The 118-meter-long Polarstern is a sophisticated floating lab that allows MOSAiC scientists to study the atmosphere, sea ice, ocean, and life. But the vessel and the equipment it carries also produce noise, light, heat, and other forms of pollution that can ruin measurements in this pristine environment.

The Polarstern‘s generators, for instance, spew a steady plume of black smoke, complicating efforts to collect air samples. “We are going to be by far the biggest source of aerosol particles in the neighborhood, and that’s a problem,” says atmospheric scientist Matthew Shupe of the National Oceanic and Atmospheric Administration and the University of Colorado (CU) in Boulder. But, he adds, “It’s also an opportunity” to understand how the arrival of more ships might affect the Arctic in the future.