Why do shipwrecks rust slowly in the deep ocean?

Answer 1

The deep water has less oxygen in it than shallower water, therefore there is less rust and corrosion. The colder, deeper water is also more dense (more pressure on it from the weight of the water above it) and the chemical combination is therefore slightly different. But I am not an oceanographer or marine scientist.

Answer 2

Rusting is oxidation of iron, and oxidation requires (you guessed it) oxygen. In shallow water, surface agitation of sea water means that oxygen is constantly being redissolved into the sea water. In deep water, there is a greater scarcity of oxygen, and so rusting takes longer.

Answer 3

Simple Answer:

Traditional iron oxidation known as "rust" does not occur rapidly in deep oceans because there is little oxygen present. In such oxygen deprived environments, more complex chemical and biological processes ultimately accomplish the process of corrosion and degradation.

More information:

The usual process of iron rusting is oxidation and requires iron and oxygen.

Only the top kilometer or less of the ocean has much dissolved oxygen.

The process of corrosion in the deep ocean is predominately through biological activity, particularly anaerobic bacteria. (The relationship between oxygen and depth is more complicated because there can be more oxygen at the very greatest depth as a result of processes that create deep ocean currents.) In addition to the cold and oxygen deprived nature of the water, objects on the ocean floor may be embedded in layer of material that further isolates it from the oxygen environment.

The wreck of the Titanic is an example of the complex deterioration process. Located at a depth of almost 4 kilometers, there is some rust but the main process causing iron decay is the action of anaerobic iron eating bacteria that reduce dissolved sulfates to form hydrogen sulfide which in turn corrodes the iron producing iron sulfide. The process has gone on for a hundred years and it is estimated that it will take about another hundred years for the Titanic to structurally destroyed. (See related links.)

Answer 4

Any thing from people to ships are more buoyant in freshwater than in saltwater. Buoyancy is determined by the downward and upward force of an object. Also, saltwater weighs more than freshwater, so objects are more buoyant in the heavier water.

Answer 5

The concentration of oxygen is lower at great depth.