Ancient POO piles reveal how climate disaster ’caused collapse’ of prehistoric American city Cahokia

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Ancient POO piles reveal how climate disaster 'caused collapse' of prehistoric American city Cahokia



ANCIENT POOP may have helped solve a 1,000-year mystery about the fall of a long-lost city named Cahokia.
Details of the ancient US city’s collapse has long baffled scientists – but the secret may have been hidden in faeces the entire time.
Cahokia Mounds State Historic Site Cahokia was a pre-Columbian Native American city that covered around six square miles – and included around 120 manmade mounds
Cahokia is a famed city that once existed near St. Louis, Missouri, but had disappeared by the time the USA was colonised by Europeans.
By using traces of human poop and environmental data, scientists were able to uncover a climate disaster – and then link it to population decline at the city.
Experts now believe that a drought was to blame for the collapse of Cahokia, which had been abandoned by 1400AD.
“The way of building population reconstructions usually involves archaeological data, which is separate from the data studied by climate scientists,” said AJ White, a lead author on the study from California State University, in the PNAS journal.
Cahokia Mounds State Historic Site The city was once large and influential, but experts now believe it collapsed after a drought that left locals unable to grow maize – the staple crop at the time
“One involves excavation and survey of archaeological remains and the other involves lake cores.
“We unite these two by looking at both kinds of data from the same lake cores.”
Researchers were able to detect “signatures” of human poop in lake core sediments that were collected from the Horseshoe Lake, near Cahokia.
These “signatures” are known as fecal stanols, and are simply molecules produced in the human gut during digestion – and then eliminated in faeces.
As native Cahokians pooped on the land, some of it would’ve run off into the lake.
And the higher the population of Cahokia at a given time, the more stanols would’ve been evident in lake sediment.
Cahokia used to be a major US city – but had collapsed by the year 1400
Sediments in lakes accumulate in layers, which allows scientists to capture exact moments of time using collected cores.
Deeper layers formed earlier, so by digging down, it’s possible to analyse soil from further back in time.
During the study, it emerged that concentrations of poop traces rose and fall roughly in line with estimates of Cahokia’s population.
This effectively proved that it was possible to track population using levels of poop in lake sediment cores.
Alamy A disastrous drought may have led to Cahokians abandoning their home city entirely
Cahokia scholar Professor Sissel Schroeder, of the University of Wisconsin-Madison, said that excavations of houses in and around Cahokia show human occupation of the site intensified by around 600 AD.
And by 1100 AD, the city – which measured six square miles – had reached its peak population of tens of thousands of people.
But by 1200, Cahokia’s population began to decline, and the site was abandoned by around 1400.
Environmental data inside the sediment cores can give clues about why this happened.
“When we use this fecal stand method, we can make these comparisons to environmental conditions that hither to now we haven’t really been able to do,” said White.
Getty – Contributor Cahokia is now an important archaeological site
Getty – Contributor Some of the Cahokia mounds still exist today for visitors to explore
Information gathered from the cores suggested that summer rain was reduced around the time of Cahokia’s population decline.
This could have prevented Cahokians from growing maize, their staple crop – forcing them to move elsewhere.
This drought could’ve been the main factor for the collapse of Cahokia is a major US city.
“When we see correlations with climate, some archaeologists don’t think climate has anything to do with it, but it’s difficult to sustain that argument when the evidence of significant changes in the climate shows people are facing new challenges,” said Schroeder.
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Astronauts could really grow their food on Mars using their own poo.
Nasa’s Peggy Whitson recently revealed the “challenging” process of doing a poo in space.
Bill Gates recently posed next to human poo to show off his “reinvented” toilet.
Are you comfortable with archaeologists of the future digging up your poo? Let us know in the comments!

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