Wrecks in the Potomac River are turning into islands, creating new, human-influenced habitats for a variety of terrestrial and aquatic species. Photo: Duke Marine Robotics and Remote Sensing Lab
Abandoned warships and bomb casings provide a substrate for marine life.
The remains of warfare create habitat for a wide range of species in the sea. That is the finding of two studies published on 25 September in Communications Earth & Environment and Scientific Data.
For the first study, researchers used underwater video to document which organisms colonise the warheads of so-called V1 bombs. These were dumped in the Lübecker Bucht – a bay in the Baltic Sea – by the Germans during the Second World War.
Biodiversity proves to be modest, at eight species. Common starfish (Asterias rubens) and Metridium dianthus sea anemones are conspicuous, but the most abundant are mud polydora worms (Polydora ciliata), which locally account for 90 per cent of the total number of organisms. At 43,184 individuals per square metre, population density is considerably higher than on the surrounding seabed without bombs, where around 8,213 individuals per square metre are found. Although researchers detect high concentrations of the toxic explosive TNT and other substances around the munitions, the local fauna appears to tolerate this.
In Scientific Data, researchers have produced a highly detailed map of shipwrecks in the Potomac River (United States). The vessels were left here during the First World War and have since become overgrown with vegetation. The new maps are intended to facilitate research into this habitat.