What happens to human remains at sea? How the decomposition of bodies in water changes

“Suspected human remains” have been found in the wreck of the submarine Titan, the US Coast Guard announced on Wednesday, June 28.

The remains are now being shipped aboard a ship to a port in the United States for testing and analysis.

But what exactly happens to human remains at sea? How long does it take for a body to decompose in water?

Read on below for everything you need to know about how bodies break down in water.

What happens to human remains at sea?

In cold water, the bacterial action that causes human bodies to swell with gas can be suppressed to such an extent that the body remains on the sea floor.

After about a week in the sea, the skin of the human body will absorb water and separate from the underlying tissues, allowing marine life, including fish, crabs and sea lice, to feast on the discarded flesh.

Cold water also stimulates the formation of adipocere, a substance with a soapy, waxy consistency.

Adipocere is formed from the fat in the body that helps protect it from decomposition.

Bodies have been recovered almost intact after several weeks from waters below 7°C, with recognizable skeletons found after a period of up to five years.

Tropical waters, such as the Arabian Sea, affect body decomposition differently, meaning that a weighted body will normally float to the surface after three or four days, exposing it to seabirds and impact from the waves.

Putrefaction — the process by which a body decays — allows scavengers to dismember the corpse within two weeks, with the remaining bones sinking to the sea floor.

Once on the sea floor, the bones can be gradually buried by sea silt. They can also degrade further over a period of months or years, depending on the acidity in the water.

Bodies have been recovered almost intact after several weeks from waters below 7°C, with recognizable skeletons found after a period of up to five years (File image)

How long does it take for a body to decompose in water?

Interestingly, the submersion of a body in water tends to slow the rate at which it decomposes, assuming there are no significant natural factors nearby, such as animal predation or certain microorganisms.

Due to the fact that seas and oceans typically lower the temperature of the human body, the growth of bacteria slows down, resulting in a slower decomposition process.

However, once removed from the water, a body can decompose more quickly compared to bodies that have been submerged.

In warm, shallow water, decomposition is rapid, meaning that a corpse can surface in just two to three days.

However, because cold water slows decay, people who drown in deep lakes at depths of 100 feet or more may never surface, as the weight of the water prevents their bodies from rising back up.