World War II Explosives, Torpedoes and Naval Mines: How Marine Life Prosper on Abandoned Weapons

In the brackish sea off the German shoreline sits a collection of World War II explosives, torpedo heads and naval mines. Discarded from boats at the end of the second world war and left behind, countless explosives have fused into clusters over the years. They form a corroding blanket on the shallow, silty seafloor of the Lübeck Bay in the western part of the Baltic.

Over the years, the Nazi arsenal was overlooked and neglected. A increasing amount of tourists came to the coastal areas and calm waters for water sports, kite surfing and entertainment venues. Beneath the surface, the weapons eroded.

We initially expected to see a lifeless zone, with no life because it was all contaminated, says the lead researcher.

When the team went searching to see what they were affecting to the marine environment, the team thought they would find a barren area, with no organisms because it was all contaminated, says a scientist.

What they discovered amazed them. Vedenin remembers his colleagues reacting with shock when the ROV first sent the images back. This was a memorable occasion, he notes.

Countless of ocean life had established habitats on the explosives, forming a regenerated habitat denser than the sea floor surrounding it.

This marine city was evidence to the persistence of marine life. Indeed surprising how much life we observe in locations that are supposed to be toxic and dangerous, he explains.

In excess of 40 sea stars had piled on to one visible fragment of TNT. They were living on iron containers, detonator compartments and carrying containers just a short distance from its explosive filling. Fish, crabs, sea anemones and bivalves were all discovered on the old munitions. It resembles a coral reef in terms of the abundance of animal life that was inhabiting the area, says Vedenin.

Surprising Population Density

An mean of more than forty thousand organisms were residing on every square metre of the explosives, researchers documented in their paper on the finding. The adjacent region was much poorer in life, with only eight thousand organisms on every square metre.

It is surprising that objects that are meant to kill everything are drawing so much life, states Vedenin. One can observe how nature adjusts after a devastating occurrence such as the World War II and how, in certain respects, marine life returns to the most dangerous areas.

Artificial Structures as Marine Environments

Artificial features such as sunken vessels, wind turbines, drilling platforms and undersea pipes can provide replacements, compensating for some of the removed marine environment. This study reveals that munitions could be comparably advantageous – the explosion of marine organisms on those in the Lübeck Bay is expected to be repeated in other locations.

Between 1946 and the post-war period, 1.6m tonnes of weapons were disposed of off the German coast. Thousands of workers loaded them in barges; a portion were placed in allocated areas, others just dumped en route. This is the first time scientists have studied how ocean organisms has responded.

Worldwide Instances of Marine Adaptation

• In the US, retired drilling platforms have transformed into reef ecosystems
• Submerged vessels from the World War I have become habitats for marine life along the Potomac in Maryland
• Tank tracks that have become habitat to reef-building organisms off Asan beach in Guam

These locations become even more important for organisms as the oceans are increasingly denuded by commercial fishing, bottom trawling and boat mooring. Shipwrecks and weapons dump sites essentially function as sanctuaries – they are not official reserves, but virtually any kind of human activity is banned, says Vedenin. Therefore a lot of species that are otherwise uncommon or diminishing, such as the cod fish, are thriving.

Coming Factors

Wherever military conflict has happened in the past 100 years, surrounding seas are often containing munitions, says Vedenin. Millions of tonnes of volatile compounds rest in our marine environments.

The locations of these explosives are insufficiently mapped, in part because of sovereign limits, restricted military information and the fact that records are buried in historic archives. They pose an detonation and security risk, as well as threat from the continuous leakage of hazardous substances.

As the German government and other countries start removing these relics, researchers aim to safeguard the habitats that have established in their vicinity. In the Lübeck Bay weapons are currently being extracted.

Researchers recommend replace these iron structures remaining from munitions with certain less dangerous, some non-dangerous structures, like maybe concrete structures, suggests Vedenin.

He now aspires that what happens in Lübeck sets a model for replacing material after weapon clearance elsewhere – because including the most destructive explosives can become framework for ocean ecosystems.