World War II Munitions, Torpedo Heads and Mines: How Marine Life Flourishes on Discarded Weapons

In the brackish waters off the Germany's shoreline sits a wasteland of Nazi bombs, torpedo heads and naval mines. Dumped from barges at the end of the second world war and left behind, thousands explosives have fused into clusters over the decades. They comprise a corroding layer on the low-depth, silty ocean floor of the Bay of Lübeck in the western tip of the Baltic Sea.

Over the decades, the Nazi arsenal was overlooked and neglected. A increasing amount of tourists flocked to the coastal areas and calm waters for jetskiing, kite surfing and amusement parks. Underwater, the munitions eroded.

We initially expected to see a desert, with nothing living there because it was all toxic, says Andrey Vedenin.

When the initial researchers went searching to see what they were affecting to the ecosystem, researchers anticipated finding a barren area, with nothing living there because it was all poisoned, explains the lead researcher.

What they observed surprised them. Vedenin recalls his scientists exclaiming in amazement when the underwater vehicle first relayed pictures. This was a memorable occasion, he says.

Numerous of marine animals had made their homes on the weapons, developing a regenerated habitat richer than the ocean bottom around it.

This underwater metropolis was evidence to the tenacity of life. Truly remarkable how much life we find in areas that are expected to be toxic and dangerous, he explains.

More than 40 sea stars had piled on to one visible fragment of TNT. They were residing on metal shells, detonator compartments and carrying containers just a short distance from its volatile core. Marine fish, crustaceans, sea anemones and mussels were all observed on the historic weapons. It resembles a marine reef in terms of the abundance of animal life that was there, says Vedenin.

Remarkable Population Density

An average of more than forty thousand animals were living on every square metre of the weapons, researchers reported in their paper on the finding. The nearby seabed was much poorer in life, with only 8,000 individuals on every square metre.

It is surprising that items that are intended to eliminate everything are attracting so much life, explains Vedenin. It's evident how the natural world adjusts after a catastrophic event such as the World War II and how, in certain respects, life finds its way to the most risky places.

Artificial Structures as Marine Environments

Artificial structures such as sunken vessels, wind turbines, drilling platforms and pipelines can offer substitutes, restoring some of the lost marine environment. This research demonstrates that weapons could be equally positive – the proliferation of marine organisms on those in the Bay of Lübeck is probable to be found elsewhere.

Between 1946 and the post-war period, 1.6m tons of weapons were dumped off the German shoreline. Thousands of people loaded them in vessels; some were placed in designated locations, the remainder just dumped during transport. This is the first time scientists have recorded how marine life has responded.

Worldwide Examples of Marine Transformation

• In the US, decommissioned drilling platforms have become reef ecosystems
• Shipwrecks from the World War I have become homes for marine life along the Potomac in Maryland
• Military vehicle parts that have become environment to reef-building organisms off Asan in Guam

These places become even more valuable for organisms as the oceans are increasingly denuded by commercial fishing, bottom trawling and boat mooring. Shipwrecks and weapons dump sites essentially act as protected areas – they are not national parks, but virtually any kind of human activity is banned, explains Vedenin. As a result a numerous of organisms that are otherwise rare or diminishing, such as the Baltic cod, are prospering.

Future Factors

Anywhere armed conflict has taken place in the past 100 years, surrounding seas are often containing munitions, states Vedenin. Many millions of tons of explosive material remain in our marine environments.

The positions of these weapons are insufficiently mapped, partially because of international boundaries, classified defense data and the fact that documents are buried in historic archives. They pose an explosion and safety risk, as well as threat from the ongoing release of hazardous substances.

As Germany and other countries begin clearing these relics, scientists aim to protect the habitats that have formed in their vicinity. In the Lübeck Bay weapons are already being cleared.

We should substitute these metal carcasses remaining from munitions with some safer, some non-dangerous materials, like maybe concrete structures, states Vedenin.

He now hopes that what happens in Lübeck establishes a precedent for replacing structures after weapon clearance in different areas – because even the most destructive weaponry can become framework for marine organisms.