World War II Explosives, Torpedo Heads and Naval Mines: How Marine Life Prosper on Discarded Armaments

In the brackish sea off the German coast rests a wasteland of World War II explosives, torpedoes and naval mines. Dumped from vessels at the conclusion of the World War II and left behind, thousands explosives have fused into clusters over the years. They comprise a corroding layer on the low-depth, silty seafloor of the Lübeck Bay in the western tip of the Baltic.

Over the decades, the explosive stockpile was overlooked and neglected. A growing number of tourists came to the sandy beaches and tranquil sea for jetskiing, kite surfing and amusement parks. Below the waves, the weapons eroded.

We initially anticipated to see a barren area, with no organisms because it was all poisoned, explains the lead researcher.

When the team went looking to see what they were doing to the marine environment, some of us anticipated finding a lifeless zone, with no life because it was all contaminated, says a scientist.

What they observed amazed them. Vedenin recounts his team members reacting with shock when the ROV first relayed pictures. This was a remarkable experience, he notes.

Countless of ocean life had established habitats on the munitions, forming a regenerated ecosystem more populous than the seabed surrounding it.

This underwater metropolis was evidence to the resilience of life. Indeed astonishing how much marine organisms we discover in areas that are considered toxic and risky, he explains.

In excess of 40 sea stars had gathered on to one visible piece of explosive material. They were living on iron containers, fuse pockets and storage boxes just a short distance from its volatile core. Fish, crustaceans, sea anemones and bivalves were all discovered on the discarded explosives. You could compare it with a reef ecosystem in terms of the quantity of fauna that was inhabiting the area, states Vedenin.

Unexpected Population Density

An average of more than 40,000 creatures were living on every square metre of the weapons, researchers wrote in their paper on the finding. The nearby seabed was much poorer in life, with only 8,000 creatures on every meter squared.

It is ironic that objects that are meant to kill everything are hosting so much marine organisms, says Vedenin. One can observe how the natural world adjusts after a catastrophic event such as the second world war and how, in some way, life establishes itself to the most dangerous locations.

Artificial Features as Ocean Habitats

Man-made features such as sunken vessels, offshore windfarms, oil rigs and undersea pipes can provide replacements, restoring some of the destroyed habitat. This study demonstrates that explosives could be similarly positive – the proliferation of life on those in the Lübeck Bay is expected to be found in other locations.

Between 1946 and the post-war period, 1.6m tons of weapons were discarded off the Germany's shoreline. Thousands of individuals placed them in boats; a portion were deposited in designated areas, others just thrown overboard during transport. This is the first time researchers have studied how ocean organisms has responded.

Worldwide Instances of Marine Adaptation

• In the US, retired oil and gas structures have become coral reefs
• Submerged vessels from the World War I have become environments for creatures along the Potomac River in the state of Maryland
• Tank tracks that have become home to reef-building organisms off Asan in Guam

These areas become even more crucial for wildlife as the seas are increasingly denuded by commercial fishing, seafloor dredging and anchoring. Shipwrecks and explosive disposal locations effectively act as protected areas – they are not official reserves, but virtually any kind of anthropogenic disturbance is banned, explains Vedenin. Therefore a numerous of marine species that are usually rare or decreasing, such as the Baltic cod, are prospering.

Coming Factors

Wherever military conflict has happened in the past 100 years, surrounding seas are often containing explosives, says Vedenin. Millions of tonnes of explosive material lie in our seas.

The locations of these munitions are poorly documented, partly because of national borders, classified armed forces records and the reality that archives are hidden in old files. They present an detonation and safety risk, as well as risk from the persistent leakage of toxic chemicals.

As Germany and other countries embark on removing these artifacts, experts plan to safeguard the ecosystems that have developed around them. In the Lübeck Bay weapons are currently being cleared.

Researchers recommend substitute these metal carcasses left from munitions with some safer, some harmless objects, like perhaps concrete structures, says Vedenin.

He currently wishes that what happens in Lübeck establishes a example for replacing structures after munitions removal in other locations – because even the most harmful explosives can become foundation for ocean ecosystems.