Shipwreck

Salinity of water
Wrecks typically decay rapidly when in seawater. There are several reasons for this:
- Iron-based metals corrode much more quickly in seawater because of the dissolved salt present; the sodium and chloride ions chemically accelerate the process of metal oxidation which, in the case of ferrous metals, leads to rust.
- Bacteria found in seawater cause the wood on ships to rot more quickly than in freshwater.