A team of scientists from the University of Gothenburg and Stockholm University has found large quantities of sulphur and iron compounds in marine archaeological wood from shipwrecks both in the Baltic Sea area and off the west coast of Sweden.
A few years ago scientists reported large quantities of sulphur and iron compounds in the salvaged 17th century warship Vasa, resulting in the development of sulphuric acid and acidic salt precipitates on the surface of the hull and loose wooden objects.
Similar sulphur compounds have now been discovered also in other shipwrecks both from the Baltic and off the west coast of Sweden, including fellow 17th century warships Kronan, Riksnyckeln and Stora Sofia, the 17th century merchant vessel in Gothenburg known as the Göta wreck, and the Viking ships excavated at Skuldelev in Denmark.
“This is a result of natural biological and chemical processes that occur in low-oxygen water and sediments,” said Dr. Yvonne Fors of the University of Gothenburg in Sweden, a co-author of the study published in the Journal of Archaeological Science.
Besides the Vasa, similar problems have previously been reported for Henry VIII’s flagship Mary Rose in the UK, which sank off Portsmouth in 1545, and the Dutch vessel Batavia in Australia, which was lost in 1629, the year after the Vasa.