Evaluation of microbial degradation of shipwrecks in the Baltic Sea

Unique historical shipwrecks in the Baltic Sea are exposed to continuous decay by specialised wood-degrading microorganisms. In this comprehensive literature study, current knowledge on microbial degradation in aquatic environments is synthesised and adapted to a cross-disciplinary context, to further understanding of the ongoing decay processes in shipwreck timbers today. Soft-rot fungi and erosion bacteria are the two most active groups of wood degraders. Their decomposition of the wood surface and interior are described, discussed, and finally compared with the available data from examined shipwrecks found in the Baltic Sea.The rate of decay depends on several parameters, such as wood species, environmental factors, duration of exposure (age of object), sediment protection, and physical damage. More consistent predictions on the longevity of wrecks are dependent on future research on the ecology of the microbes, combined with investigations of the historical wrecks themselves. This research is essential for successful in-situ protection and long-term preservation of significant historical shipwrecks.