Microbial Biomarkers Raise Possibilities of Ancient Humans Cooking in Hot Springs

An archeological site that contained early human remains in Olduvai Gorge, Tanzania, might have also contained hot springs where human ancestors boiled their food, a new study suggests.

A team of researchers from the Massachusetts Institute of Technology (MIT) in the United States and the University of Alcala in Spain has found microbial biomarkers that suggest the presence of hot springs in the Northern Tanzania site.

The study, led by Marie Sklodowska-Curie Fellow Ainara Sistiaga from MIT and University of Copenhagen, has been published in the journal Proceedings of the National Academy of Sciences, September 14.

Early Humans Living in Hydrothermally Active Areas

The close location of these hydrothermal features, according to the study, creates the possible scenario that our early ancestors have used the hot springs in the preparation of their food, like boiling fresh kills before humans were thought to have used fire in their food.

"As far as we can tell, this is the first time researchers have put forth concrete evidence for the possibility that people were using hydrothermal environments as a resource, where animals would've been gathering, and where the potential to cook was available," explained Roger Summons, Schlumberger Professor of Geobiology in the Department of Earth, Atmospheric, and Planetary Sciences in MIT.

In 2016, Sistiaga was a part of an archaeological dig at Olduvai Gorge, working with members of the Olduvai Paleoanthropology and Paleoecology Project who were collecting samples in the 3-kilometer layer of exposed rock dated at 1.7 million years ago. Researchers observed that there was a dark clay layer underneath the mostly sandy site, with the darker, deeper layer dated at 1.8 million years ago.

RELATED: Archaeologists Unearthed 3,800-Year-Old Tomb Of An Ancient Egyptian Woman In Intact Position

"Something was changing in the environment, so we wanted to understand what happened and how that impacted humans," Sistiaga explained, adding that the original plan was to understand the change in the landscape with respect to climate changes and its possible effect on the lifestyle of the early settlers in the region. The evidence suggests that the East African season shifted from wet and green landscapes to a more arid, grassier terrain.

Microbial Biomarkers Extracted from Sedimentary Samples

Sistiaga discovered lipids embedded in the sediments she recovered from the site. However, these were distinct from plant-derived lipids she was familiar with, referring to Summons. Roger Summons later identified the unique lipids as being similar to specific bacteria they have previously studied almost two decades ago. These lipids, taken by Sistiaga from Tanzania, were similar to those produced by bacteria that Summons and his team previously observed from the hot springs of the Yellowstone National Park, in the United States.

One of the bacterium identified, Thermocrinis ruber, is a hyperthermophilic microorganism that lives in hot waters like boiling hot springs and their outflow channels. Since bacteria found in Olduvai Gorge 1.7 million years are similar to those in Yellowstone hot springs, leading researchers to suggest that hydrothermal features, like hot springs, might have been present in the Tanzanian gorge during the same period.

RELATED: Gas Stoves are Making People Sicker and Exposing Children to a Higher Risk for Asthma, Study Claims

While the possible markers that suggest the presence of hot springs in the area have been found, there was still no concrete evidence explaining how they might have cooked with the hot springs. Researchers propose a variety of scenarios of how it could've been possible.

"We can prove in other sites that may be hot springs were present, but we would still lack evidence of how humans interacted with them," Sistiaga said.

Check out more news and information on Archaeology in Science Times.