Site Management

The Natural Environment of the Shipwreck Vrouw Maria (1771) in the Northern Baltic Sea: an assessment of her state of preservation

“…All the visible ingots are spread around the hold on top of cargo without contact with the hull. In principle on‐site deterioration can be slowed down by remedial action based on knowledge of physical, biological and chemical processes which can be reduced (Oxley and Gregory, 2002: 720).…”

“…Oxygen is the limiting factor for the colonization and deterioration of wood. Aerobic bacteria and fungi cannot attack below the sediment surface; therefore, burying wood to limit the supply of oxygen to bacteria and fungi is the best way to control their attack (Oxley and Gregory, 2002: 720). It can be argued that the abundant existence of sulphur‐bacteria carpets indicates very low oxygen levels in the hold, and such an environment within the bulk of the cargo would enhance the preservation even of organic objects.…”

“…These processes in turn depend on the geographical location of the wreck, and its depth. In open‐water marine environments, boring molluscs such as shipworm ( Teredo navalis ) and the crustacea genus Limnoria will cause rapid deterioration of wood (Oxley and Gregory, 2002: 717; Laitinen, 2007: 35). Biological wood‐degrading factors and organisms at the Vrouw Maria wreck‐site have already been studied, by installing experimental wood samples on the site, in both aerobic and anaerobic environments.…”

“…Dissolved oxygen content, temperature and salinity should be monitored in order to investigate the potential for future colonization at any given site. However, while biodegradation and corrosion of artefacts are important factors for long‐term site management, the immediate problems may be physical forces of water‐currents, or destabilizing sedimentary regimes (Oxley and Gregory, 2002: 717; Laitinen, 2007: 35). The accumulation of sediments at the Vrouw Maria site was very low, leaving most of the wreck exposed.…”

Benthic conditions around a historic shipwreck: Vrouw Maria (1771) in the northern Baltic proper

“…Thus the presence of the wreck seems to have induced site-specific hydrodynamic processes which were capable of affecting first the seafloor geomorphology and organic content and then its biology (McNinch et al, 2006;Quinn, 2006;Leino et al, 2011). Although biodegradation of artefacts is an important factor for long-term site management of shipwrecks, physical forces of water currents or destabilizing sedimentary regimes, may be more immediate problems (Oxley and Gregory, 2002). However, the accumulation of sediments was very low at the Vrouw Maria site, leaving most of the wreck exposed (Leino et al, 2011) and even though the site was thought to be affected by strong currents, water movements and low temperatures, it could overall be regarded as quite stable (Palma, 2004;Leino et al, 2011).…”