Can Salt Water Dissolve Bones?
Bones do dissolve in salt water, but not as a direct result of chemical interaction with the salt. Creatures and microbes continuously break down all living tissue – also on the ocean floor. The speed depends on a series of factors such as water temperature, oxygen content, acidity, and the creatures and microbes available. Under favourable conditions, a dead creature in the ocean is turned into a "naked" skeleton in 3-4 days, whereas the bones will be gone after about a year.
If the animal had died on dry land, it would often take at least 10 years for the skeleton to disappear completely. The longest process takes place in dry, warm air, in which microbes and bacteria have the most difficult living conditions. Bones are made up of living cells with blood vessels and nerves like any other tissue. The hard parts consist of a porous network of protein plus calcareous and phosphorous minerals, which bacteria can dissolve and feed on.