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

In the slightly salty waters off the Germany's coast lies a collection of World War II explosives, torpedo heads and naval mines. Thrown off vessels at the conclusion of the second world war and forgotten about, countless explosives have become matted together over the years. They create a decaying carpet on the shallow, silty seafloor of the Bay of Lübeck in the western tip of the Baltic Sea.

Over the years, the Nazi arsenal was overlooked and forgotten about. A growing number of tourists came to the sandy beaches and calm waters for water sports, kiteboarding and entertainment venues. Below the waves, the munitions decayed.

Some of us thought to see a lifeless zone, with nothing living there because it was all poisoned, explains the lead researcher.

When the team went looking to see what they were doing to the ecosystem, the team thought they would find a desert, with no life because it was all contaminated, states Andrey Vedenin.

What they observed astonished them. Vedenin recounts his colleagues exclaiming in amazement when the ROV first relayed pictures. This was a memorable occasion, he notes.

Thousands of ocean life had settled among the munitions, creating a regenerated marine community more populous than the ocean bottom surrounding it.

This underwater metropolis was proof to the resilience of life. It is actually astonishing how much marine organisms we find in places that are supposed to be hazardous and harmful, he explains.

More than 40 sea stars had clustered on to one visible chunk of TNT. They were residing on steel casings, detonator compartments and carrying containers just centimetres from its dangerous content. Marine fish, crustaceans, sea anemones and mussels were all discovered on the old munitions. You could compare it with a reef ecosystem in terms of the quantity of creatures that was present, notes Vedenin.

Unexpected Creature Concentration

An average of more than 40,000 organisms were dwelling on every meter squared of the weapons, scientists wrote in their research on the discovery. The nearby seabed was much sparser, with only eight thousand organisms on every square metre.

It is paradoxical that objects that are intended to kill all life are drawing so much marine organisms, states Vedenin. It's evident how the natural world adapts after a major disaster such as the World War II and how, in certain respects, marine life finds its way to the most hazardous areas.

Man-made Structures as Ocean Habitats

Man-made constructions such as sunken vessels, offshore windfarms, drilling platforms and undersea pipes can provide substitutes, compensating for some of the removed marine environment. This study demonstrates that weapons could be comparably beneficial – the explosion of marine organisms on those in the Lübeck Bay is expected to be duplicated elsewhere.

Between 1946 and the post-war period, 1.6 million tonnes of weapons were dumped off the Germany's shoreline. Numerous of workers placed them in vessels; some were placed in specific sites, others just thrown overboard while traveling. This is the first time researchers have recorded how marine life has responded.

Global Instances of Ocean Transformation

• In the US, retired drilling platforms have transformed into reef ecosystems
• Sunken ships from the first world war have become habitats for wildlife along the Potomac River in Maryland
• Tank tracks that have become home to reef-building organisms off Asan beach in Guam

These places become even more important for marine life as the marine environments are increasingly stripped by commercial fishing, bottom trawling and anchoring. Shipwrecks and weapons dump sites practically serve as sanctuaries – they are not official reserves, but nearly any kind of anthropogenic disturbance is restricted, states Vedenin. Therefore a many of marine species that are usually uncommon or decreasing, such as the cod fish, are prospering.

Future Factors

Wherever military conflict has occurred in the last century, adjacent waters are usually containing munitions, explains Vedenin. Many millions of tons of volatile compounds rest in our oceans.

The sites of these munitions are inadequately mapped, partially because of international boundaries, secret defense data and the fact that documents are stored in historical records. They create an detonation and safety danger, as well as risk from the persistent release of toxic chemicals.

As the German government and other countries begin extracting these artifacts, researchers plan to protect the marine communities that have established in their vicinity. In the Bay of Lübeck munitions are already being cleared.

We should substitute these steel remains left from munitions with some more secure, some non-dangerous objects, like possibly man-made habitats, states Vedenin.

He presently wishes that what happens in Lübeck sets a model for replacing material after weapon clearance in other locations – because including the most harmful explosives can become framework for ocean ecosystems.