Sunken ammunition: danger with long-term effects

Stormy weather and strict hygiene regulations put the science crew to the test. After a delay of almost two days due to weather conditions and several days of scheduled quarantine, the captain of the HEINCKE gave the command "cast off" on Thursday morning and set course for Helgoland. The research team of the "North Sea Wrecks" project collected samples around the wreck of the warship SMS MAINZ off the North Sea island. They will be used to investigate the extent to which the ship from the First World War, which was sunk together with its ammunition, secretes toxic substances.

They have been resting on the bottom of the North Sea for almost 80 sometimes 100 years. For example, west of Helgoland - wrecks of warships that sank there in battle during the First and Second World Wars. Still on board: weapons, ammunition, oils and fuel. Researchers suspect up to 1.3 million tonnes of ammunition in the German part of the North Sea alone.

The EU-funded research project "North Sea Wrecks" (NSW) with the participation of the German Maritime Museum (DSM) / Leibniz Institute for Maritime History and the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) is investigating the dangers to humans and the environment posed by the war legacies and the history behind the wrecks. To this end, the researchers are working across borders and interdisciplinary with other experts from Germany, Belgium, Denmark, Norway and the Netherlands. NSW is the successor to a project for which researchers investigated munitions in the Baltic Sea. For NSW, the war wrecks at the bottom of the North Sea, including their cargo, are now moving into the research focus. There is much more war equipment lying dormant on the North Sea floor than in the Baltic Sea.

Under strict hygienic conditions, the German-Belgian team spent six days on board the HEINCKE, four days researching west of Helgoland, taking various samples from the environment of the SMS MAINZ and releasing mussels, which will be recovered at the end of June. The team led by AWI marine biologist Dr Matthias Brenner hopes that the sediment and mussel samples will provide insights into, for example, which pollutants are emitted by the munitions and the wrecks, whether they are absorbed by the organisms living there and, if so, whether the organism is affected by the substances or not.

A robot dived to the wreck and explored the surroundings. Thanks to the latest technology, the team produced two- and three-dimensional scans that give precise indications of the condition and environment of the wreck. Dr Philipp Grassel from the DSM calls this "basic work". "I am particularly attracted by the tension between danger and habitat. In the meantime, the wrecks have developed into habitats," says the expert in maritime archaeology.

The SMS MAINZ has been resting in the North Sea for around 107 years. The British fleet sank the small cruiser in the sea battle off Helgoland in August 1914. The NSW project team researched old files to find out how the ship was equipped before it sank: "It was equipped with rapid-fire cannons and torpedoes and probably still had some ammunition on board at the time of the sinking," says Grassel.

Further excursions are being planned. Samples will then be taken from the SMS ARIADNE, the V187 and other wrecks. A diving team will collect sediments and organisms from the wreck hull.

The results of the NSW project will be presented in a travelling exhibition from August 2021. After the start in Bremerhaven, it will make stops in all countries participating in the project.

The North Sea Wrecks project has a budget of over four million euros and is funded by the EU through the Interreg programme. DAS DSM coordinates it from Bremerhaven and enables, over a period of four years, a close cooperation of about 30 European project partners on several levels.