Scientists Found Marine Life Where They Didn't Expect It

An undersea submersible has spotted crabs, worms, and fish thriving on the surfaces of World War II explosives thought to be toxic to marine life. At a former weapons dump site in the Baltic Sea, scientists found more creatures living on top of warheads than in the surrounding seabed. "We were prepared to see significantly lower numbers of all kinds of animals," study author Andrey Vedenin, with the Senckenberg Research Institute in Germany, tells the AP. "But it turned out the opposite."

In the new study, researchers filmed networks of anemones, starfish, and other underwater life in the Bay of Luebeck off the coast of Germany. They were lurking on pieces of V-1 flying bombs used by Nazi Germany. The research was published Thursday in the journal Communications Earth & Environment. Per a press release, Vedenin and his colleagues' analysis found there were around 43,000 organisms per square meter on the munitions compared with around 8,200 organisms per square meter in the sediment. The concentrations of explosive compounds were detected at levels as high as 2.7mg per liter, "a level estimated to be potentially fatally toxic to marine life."

Why would sea creatures make their home on contaminated weapons? They could be drawn to the hard surfaces, which are in short supply in the Baltic Sea. The seafloor is mainly a flat bed of mud and sand, because stones and boulders were fished out of the water for construction in the 1800s and 1900s, Vedenin says. The area is also fairly isolated from human activity because of the chemicals, creating a somewhat protective bubble for the critters to thrive despite some toxic trade-offs.

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Scientists hope to calculate how much contamination was absorbed by sea life. Another important next step is to see what happens after the critters settle and whether they're capable of reproducing, says University of Georgia ecologist James Porter, who wasn't involved with the research. Past conflicts have left their mark on the world's oceans, Vedenin says. German waters alone contain about 1.6 million tons of dumped weapons, mostly from the two world wars in the 20th century—and Germany is painstakingly trying to recover them. Dumped relics can contain nuclear and chemical remnants, as well as explosives like TNT.