Friday, September 20, 2024

"The Big Baltic Bomb Cleanup"

From Hakai Magazine, September 5:

The ocean became a dumping ground for weapons after Allied forces defeated the Nazis. Now a team of robots and divers are making the Baltic Sea safer.

Aboard the Alkor, a 55-meter oceanographic vessel anchored in the Baltic Sea several kilometers from the German port city of Kiel, engineer Henrik Schönheit grips a joystick-like lever in his fist. He nudges the lever up, and a one-of-a-kind robotic sea crawler about the size of a two-seat golf cart responds, creeping forward along the seafloor on rubber caterpillar tracks 12 meters below the ship. As the crawler inspects Kiel bay’s sandy terrain, a live video stream beams up to a computer screen in a cramped room aboard the ship. The picture is so crystalline that it’s possible to count the tentacles of a translucent jellyfish floating past the camera. A scrum of scientists and technicians ooh and ah as they huddle around the screen, peering over Schönheit’s shoulder.

The bright-yellow robot is the Norppa 300, the newest fabrication of the explosive ordnance disposal company SeaTerra, which operates out of northern Germany. SeaTerra’s cofounder Dieter Guldin rates as one of Europe’s canniest experts for salvaging sunken explosives. Now, after years of experience clearing the seafloor of hazards for commercial operations, and campaigning the German government for large-scale remediation, SeaTerra is one of three companies participating in the first-ever mission to systematically clear munitions off a seafloor in the name of environmental protection. The arduous and exacting process of removing and destroying more than 1.5 million tonnes of volatile munitions from the Baltic and North Sea basins—an area roughly the size of West Virginia—is more urgent by the day: the weapons, which have killed hundreds of people who have come into accidental contact with them in the past, are now corroded. Their casings are breaking apart and releasing carcinogens into the seas.

SeaTerra’s top technicians aboard the Alkor are testing the Norppa 300’s basic functions in the wild prior to the project’s start this month, in early September 2024: ensuring that its steering, sonar imaging of the seafloor, chemical sampler, and video feed are fine-tuned. Everyone huddled in the ship’s dry lab watches rapt as the crawler bumps up against a vaguely rectangular object the size of a bar fridge. It’s largely obscured by seaweed and, from the looks of it, home to a lone Baltic flounder that’s swimming around the base. Aaron Beck, senior scientist at Geomar Helmholtz Centre for Ocean Research, a German marine research institute working alongside SeaTerra, identifies it as an ammunition crate. “Look, the flatness there, the corner. That’s not of the natural world,” he exclaims.


Dumped munitions lie in waters across the world but are ubiquitous in German waters. In the aftermath of the Second World War, all the conflict parties, including the United Kingdom, Russia, Japan, and the United States, had to divest themselves of armaments. “They didn’t want [them] on land, and facilities to destroy [them] were too few,” explains Anita Künitzer of the German environment agency. Dumping at sea, a practice held over from the First World War, was the obvious choice.

In occupied Germany, British forces established underwater disposal zones—one of which lies near Kiel bay. “But,” says Guldin, “on their way to the designated dumping grounds, they also just threw hardware overboard.” Grainy black-and-white film footage shows British sailors busily operating multiple conveyor belts to cast crate after crate of leftovers into the sea. Whole ships and submarines packed with live munitions were scuttled in the rush to disarm the Germans.

Experts estimate that a ginormous 1.6 million tonnes of conventional munitions and another 5,000 tonnes of chemical weapons lie decomposing off Germany alone in the North and Baltic Seas, most from the Second World War. (Because of its busy ports, the North Sea received four times as much as the Baltic.) If all that weaponry were lined up, it would stretch from Paris to Moscow, about 2,500 kilometers! “Nowhere in German waters is there a square kilometer of seabed without munitions,” says Guldin....

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