Scientists solve 5,000-year-old cold case by testing Stone Age skeleton for algae

British scientists have cracked a 5,000-year-old cold case by testing for algae in the bone marrow of a Stone Age skeleton.

Experts from the University of Southampton applied the technique to the man who was found in a mass grave on the Chilean coast, but whose cause of death remained a mystery.

They hope that the technique can be used on historic coastal mass graves across the world.

Prof James Goff of the University of Southampton, who led the study, said: “Mass burials have often been necessary after natural disasters such as tsunamis, floods or large storms.

“However, we know very little about whether prehistoric mass burial sites near coastlines could be the result of natural disasters or other causes such as war, famine and disease.

“This gave us our light bulb moment of developing an enhanced version of a modern forensic test to use on ancient bones.”

The Chilean man, it turned out, was not the victim of a natural disaster or major catastrophe.

Test results found a variety of marine particles which suggested he drowned in saltwater, which included fossilised algae, parasite eggs and sediment.

Others in the mass grave, meanwhile, did not have the same markers, suggesting that they did not drown and that this was an isolated incident.

Further evidence, including the condition of the individual’s bones which showed signs of frequent harpooning, rowing and harvesting of shellfish, and his age of between 35 and 45, suggested that he was a fisherman.

He was also likely to have drowned in shallow water, said Prof Goff.

“We could see that the poor man swallowed sediment in his final moments and sediment does not tend to float around in sufficient concentrations in deeper waters.”

Modern forensics can confirm drowning as the cause of death in recent victims by testing for diatoms - a group of algae found in oceans, freshwater and soils - inside the bones of the victims.

If diatoms are discovered in the bones of victims’ bodies, it is likely that they drowned because, had they died before entering the water, they would not have swallowed any.

The test had, until now, never been successfully used to conclude drowning in prehistoric human remains.