World War II Shipwreck Leaks Pollutants Into North Sea, Study Finds
|
European researchers found heavy metals, arsenic and other pollutants near the fishing trawler, which was converted into a patrol boat by Germany in the Second World War.
By Christine Hauser
Oct. 22, 2022
For more than 80 years, the wreck of a fishing trawler used as a German patrol boat during World War II has lain undisturbed at the bottom of the North Sea, where it capsized with its arsenal and crew after being bombed by British warplanes.
But as the vessel, known as the V-1302 John Mahn, corrodes and ages, its legacy as a wartime relic is still evolving, according to a study published in Frontiers in Marine Science this week.
Researchers detected pollutants in the marine environment that had leaked from the ship’s hull, fuel and munitions decades after it sank. The study is the latest in a growing effort to evaluate the environmental impact of shipwrecks, tracing not only how they got to their watery resting places but also what happened to them afterward.
“The general public is often quite interested in shipwrecks because of their historical value, but the potential environmental impact of these wrecks is often overlooked,” said Josefien Van Landuyt, the study’s lead author, a Ph.D. student at Ghent University in Belgium.
The John Mahn project was part of a European program, North Sea Wrecks, that studies the environmental impact of shipwrecks in the North Sea. Similar work has looked at warship wrecks in Pearl Harbor and around the Orkney Islands. Other recent research focused on the microbiomes surrounding wooden ships that sank in the Gulf of Mexico.
The North Sea is a rich ground for examination, littered with thousands of ships, aircraft, munitions, petroleum and explosives, mostly from the First and Second World Wars. The John Mahn study aimed to address a lack of scientific information about how, if at all, they are oozing pollutants as they corrode.
“Wrecks can be artificial reefs and therefore be a habitat for marine life,” said Philipp Grassel, an archaeologist and historian with the German Maritime Museum, which is contributing to the North Sea program. “They can be protected places due to their culture heritage value, or they can — especially naval wrecks — be protected war graves.”
But because wartime shipwrecks may hold ordnance and fuel, he added, they can pose a threat to marine ecosystems.
On Feb. 12, 1942, British bombs struck the propeller shaft and boiler room of the John Mahn, a 157-foot trawler adapted for war by Germany. It sank off the coast of Belgium, taking its crew of 11 sailors into the deep.
In interviews, Ms. Van Landuyt and other researchers said they singled out the wreck because it lies clear of shipping lanes, and divers told them there were munitions onboard.
In 2019, the team set to work, analyzing surrounding sediment and steel hull samples and finding heavy metals, chemicals, arsenic and explosive compounds. According to the study, the marine environment and chemistry “on and around” the ship “is still influenced by the wreck” even after 80 years.
But the findings do not indicate an impending environmental disaster. The study showed that microbes in areas around the ship had been degrading oil that had leaked from the vessel, decades after it sank. That could be helpful, because it would be costly and impractical to remove the wreck, said Erin Field, an assistant professor of biology at East Carolina University.
“The bright side of this is if these microbes are able to degrade the oil, that is good for the environment, because they will remove it as a contaminant,” said Dr. Field, who reviewed the study. “We don’t know how fast, but if they are capable, it would be a benefit.”
“We have a lot of unanswered questions on the impact of wrecks on the environment nearby,” she added.
More than 8,000 shipwrecks from the world wars litter the seas. A 2021 study by scientists in Britain raised concerns about oil pollution from these wrecks, among other environmental impacts.
That study examined the marine environment surrounding the H.M.S. Royal Oak, which was torpedoed by a German submarine and sank off the Orkney Islands in 1939. It leaked oil in the 1960s and 1990s, and though some oil was removed from its tanks, an estimated 697 metric tons, or about 768 U.S. tons, remained, the study said. Tests confirmed there were “minimal impacts” from leaking oil on the surrounding environment.
In a 2016 project, a University of Nebraska-Lincoln team studied the corrosion of the U.S.S. Arizona, which sank in the attack on Pearl Harbor in 1941. The researchers estimated that the battleship held hundreds of thousands of gallons of oil but could remain structurally stable because of a buildup of organisms on the vessel.
Maarten De Rijcke, a senior investigator on the John Mahn project, said it was important to monitor wrecks because, though they continue to evolve as they age, they must be left undisturbed as war graves.
“You can’t go in there and remedy the wreck,” he said. “What we would like to do is to be able to advise policymakers and assess each wreck individually. It is a stoplight system.”
|
Replies are disabled on threads older than 7 days.
|
|