Off Hiiumaa island, German warship wrecks from 1916 are ticking ecological time bombs, holding thousands of liters of oil that could pollute Baltic Sea coastlines if released.
The German torpedo boats S57, V72 and V75 sank in November 1916 after straying into a minefield during a failed attack on the port of Paldiski.
A new study by researchers from the Estonian Maritime Museum (EMM) and Finland, led by Ivar Treffner, assessed the wrecks and the environmental threat they pose.
At the time, navies had only just begun transitioning from coal to liquid fuel. The ships went down carrying thousands of liters of heavy fuel oil, which remains trapped inside their hulls today.
The wrecks are not currently leaking, and researchers do not expect their hulls to collapse in the near future, but as the metal continues to corrode on the seabed, recovering the oil safely will become more difficult.
The Baltic Sea's cold, low-salinity, oxygen-poor water helps preserve the wrecks, while the scarcity of oil-degrading bacteria slows the breakdown of any fuel released. This same combination of conditions is also keeping the potential pollution trapped inside their hulls.
Researchers warn, however, that the threat should be addressed before the wrecks deteriorate further and the oil spills directly into coastal waters, potentially causing a major environmental disaster in the Baltic.
Their findings were published in the journal Heritage.
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