The Baltic Sea has a low salt concentration of on average about 0.5-0.7%, compared to the Atlantic Ocean's average salinity of 3.5%. This lower salinity is caused by the influx of fresh water from rivers and the limited exchange of water with the North Sea, which is the only connection between the Baltic Sea and the Atlantic Ocean. The lower salinity slows down the decomposition process caused by microorganisms and marine organisms that typically feed on wood and organic materials, which contributes to better preservation of shipwrecks.
Great Lakes
The Great Lakes are also low salinity freshwater lakes, with salinity levels ranging from 0.1% to 0.8%, making them less corrosive than oceans and other salt water bodies. The colder water temperatures and the absence of strong currents in the Great Lakes also contribute to the better preservation of shipwrecks. Cold temperatures slow down the activity of microorganisms, and the lack of strong currents helps prevent damage to shipwrecks by wave action. Additionally, the Great Lakes have a more limited marine life compared to the Atlantic Ocean, with a lower presence of organisms that feed on wood and other materials.
