Did our early ancestors boil their food in hot springs?
Scientists have found evidence of hot springs near sites where ancient hominids settled, long before the control of fire.
The region has preserved many fossils and stone tools, indicating that early humans settled and hunted there.
Now a team led by researchers at MIT and the University of Alcalá in Spain has discovered evidence that hot springs may have existed in Olduvai Gorge around that time, near early human archaeological sites. The proximity of these hydrothermal features raises the possibility that early humans could have used hot springs as a cooking resource, for instance to boil fresh kills, long before humans are thought to have used fire as a controlled source for cooking.
"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," says Roger Summons, the Schlumberger Professor of Geobiology in MIT's Department of Earth, Atmospheric, and Planetary Sciences (EAPS).
Summons and his colleagues have published their findings today in the Proceedings of the National Academy of Sciences. The study's lead author is Ainara Sistiaga, a Marie Skłodowska-Curie fellow based at MIT and the University of Copenhagen. The team includes Fatima Husain, a graduate student in EAPS, along with archaeologists, geologists, and geochemists from the University of Alcalá and the University of Valladolid, in Spain; the University of Dar es Salaam, in Tanzania; and Pennsylvania State University.
An unexpected reconstruction
In 2016, Sistiaga joined an archaeological expedition to Olduvai Gorge, where researchers with the Olduvai Paleoanthropology and Paleoecology Project were collecting sediments from a 3-kilometer-long layer of exposed rock that was deposited around 1.7 million years ago. This geologic layer was striking because its sandy composition was markedly different from the dark clay layer just below, which was deposited 1.8 million years ago.
"Something was changing in the environment, so we wanted to understand what happened and how that impacted humans," says Sistiaga, who had originally planned to analyze the sediments to see how the landscape changed in response to climate and how these changes may have affected the way early humans lived in the region.
It's thought that around 1.7 million years ago, East Africa underwent a gradual aridification, moving from a wetter, tree-populated climate to dryer, grassier terrain. Sistiaga brought back sandy rocks collected from the Olduvai Gorge layer and began to analyze them in Summons' lab for signs of certain lipids that can contain residue of leaf waxes, offering clues to the kind of vegetation present at the time.
"You can reconstruct something about the plants that were there by the carbon numbers and the isotopes, and that's what our lab specializes in, and why Ainara was doing it in our lab," Summons says. "But then she discovered other classes of compounds that were totally unexpected."
An unambiguous sign
Within the sediments she brought back, Sistiaga came across lipids that looked completely different from the plant-derived lipids she knew. She took the data to Summons, who realized that they were a close match with lipids produced not by plants, but by specific groups of bacteria that he and his colleagues had reported on, in a completely different context, nearly 20 years ago.
The lipids that Sistiaga extracted from sediments deposited 1.7 million years ago in Tanzania were the same lipids that are produced by a modern bacteria that Summons and his colleagues previously studied in the United States, in the hot springs of Yellowstone National Park.
One specific bacterium, Thermocrinis ruber, is a hyperthermophilic organism that will only thrive in very hot waters, such as those found in the outflow channels of boiling hot springs.
"They won't even grow unless the temperature is above 80 degrees Celsius [176 degrees Fahrenheit]," Summons says. "Some of the samples Ainara brought back from this sandy layer in Olduvai Gorge had these same assemblages of bacterial lipids that we think are unambiguously indicative of high-temperature water."
That is, it appears that heat-loving bacteria similar to those Summons had worked on more than 20 years ago in Yellowstone may also have lived in Olduvai Gorge 1.7 million years ago. By extension, the team proposes, high-temperature features such as hot springs and hydrothermal waters could also have been present.
"It's not a crazy idea that, with all this tectonic activity in the middle of the rift system, there could have been extrusion of hydrothermal fluids," notes Sistiaga, who says that Olduvai Gorge is a geologically active tectonic region that has upheaved volcanoes over millions of years — activity that could also have boiled up groundwater to form hot springs at the surface.
The region where the team collected the sediments is adjacent to sites of early human habitation featuring stone tools, along with animal bones. It is possible, then, that nearby hot springs may have enabled hominins to cook food such as meat and certain tough tubers and roots.
"The authors' comprehensive analyses paint a vivid picture of the ancient Olduvai Gorge ecosystem and landscape, including the first compelling evidence for ancient hydrothermal springs," says Richard Pancost, a professor of biogeochemistry at the University of Bristol, who was not involved in the study. "This introduces the fascinating possibility that such springs could have been used by early hominins to cook food."
"Why wouldn't you eat it?"
Exactly how early humans may have cooked with hot springs is still an open question. They could have butchered animals and dipped the meat in hot springs to make them more palatable. In a similar way, they could have boiled roots and tubers, much like cooking raw potatoes, to make them more easily digestible. Animals could have also met their demise while falling into the hydrothermal waters, where early humans could have fished them out as a precooked meal.
"If there was a wildebeest that fell into the water and was cooked, why wouldn't you eat it?" Sistiaga poses.
While there is currently no sure-fire way to establish whether early humans indeed used hot springs to cook, the team plans to look for similar lipids, and signs of hydrothermal reservoirs, in other layers and locations throughout Olduvai Gorge, as well as near other sites in the world where human settlements have been found.
"We can prove in other sites that maybe hot springs were present, but we would still lack evidence of how humans interacted with them. That's a question of behavior, and understanding the behavior of extinct species almost 2 million years ago is very difficult, Sistiaga says. "I hope we can find other evidence that supports at least the presence of this resource in other important sites for human evolution."
This research was supported, in part, by the European Commission (MSCA-GF), the NASA Astrobiology Institute, and the Government of Spain.
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Northwell Health CEO Michael Dowling has an important favor to ask of the American people.
- Michael Dowling is president and CEO of Northwell Health, the largest health care system in New York state. In this PSA, speaking as someone whose company has seen more COVID-19 patients than any other in the country, Dowling implores Americans to wear masks—not only for their own health, but for the health of those around them.
- The CDC reports that there have been close to 7.9 million cases of coronavirus reported in the United States since January. Around 216,000 people have died from the virus so far with hundreds more added to the tally every day. Several labs around the world are working on solutions, but there is currently no vaccine for COVID-19.
- The most basic thing that everyone can do to help slow the spread is to practice social distancing, wash your hands, and to wear a mask. The CDC recommends that everyone ages two and up wear a mask that is two or more layers of material and that covers the nose, mouth, and chin. Gaiters and face shields have been shown to be less effective at blocking droplets. Homemade face coverings are acceptable, but wearers should make sure they are constructed out of the proper materials and that they are washed between uses. Wearing a mask is the most important thing you can do to save lives in your community.
Two massive clouds of dust in orbit around the Earth have been discussed for years and finally proven to exist.
- Hungarian astronomers have proven the existence of two "pseudo-satellites" in orbit around the earth.
- These dust clouds were first discovered in the sixties, but are so difficult to spot that scientists have debated their existence since then.
- The findings may be used to decide where to put satellites in the future and will have to be considered when interplanetary space missions are undertaken.
What are they?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODgyMDA0NC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNTM1ODc0Mn0.NH33LuauIo__sUBi4tvhwxDcsvhflDFD-Nhx9FjlSNk/img.jpg?width=1245&coordinates=148%2C0%2C149%2C0&height=700" id="cec96" class="rm-shortcode" data-rm-shortcode-id="acb78abe2ab46a17e419ad30906751d6" data-rm-shortcode-name="rebelmouse-image" />
Artist's impression of the Kordylewski cloud in the night sky (with its brightness greatly enhanced) at the time of the observations.
G. Horváth<p>The<a href="https://en.wikipedia.org/wiki/Kordylewski_cloud" target="_blank"> Kordylewski clouds</a> are two dust clouds first observed by Polish astronomer Kazimierz Kordylewski in 1961. They are situated at two of the <a href="https://www.space.com/30302-lagrange-points.html" target="_blank">Lagrange points</a> in Earth's orbit. These points are locations where the gravity of two objects, such as the Earth and the Moon or a planet and the Sun, equals the centripetal required to orbit the objects while staying in the same relative position. There are five of these spots between the Earth and Moon. The clouds rest at what are called points four and five, forming a triangle with the clouds and the Earth at the three corners.</p><p>The clouds are enormous, taking up the same space in the night sky as twenty lunar discs; covering an area of 45,000 miles. They are roughly 250,000 miles away, about the same distance from us as the Moon. They are entirely comprised of specks of dust which reflect the light of the sun so faintly most astronomers that looked for them were unable to see them at all. </p><p>The clouds themselves are probably ancient, but the model that the scientists created to learn about them suggests that the individual dust particles that comprise them can be blown away by solar wind and replaced by the dust from other cosmic sources like comet tails. This means that the clouds hardly move but are <a href="https://www.nationalgeographic.com/science/2018/11/news-earth-moon-dust-clouds-satellites-planets-space/" target="_blank">eternally changing</a>. </p>
How did they discover this?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODgyMDAzNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1Nzc4MjQ4MX0.7uU9OqmQcWw5Ll1UXAav0PCu4nTg-GdJdAWADHanC7c/img.jpg?width=1245&coordinates=0%2C180%2C0%2C181&height=700" id="952fb" class="rm-shortcode" data-rm-shortcode-id="a778280a20f1c54cd2c14c8313224be2" data-rm-shortcode-name="rebelmouse-image" />
"In this picture the central region of the Kordylewski dust cloud is visible (bright red pixels). The straight tilted lines are traces of satellites."
J. Slíz-Balogh<p>In their study published in the <a href="https://academic.oup.com/mnras" target="_blank">Monthly Notices of the Royal Astronomical Society</a>, Hungarian astronomers Judit Slíz-Balogh, András Barta, and Gábor Horváth described how they were able to find the dust clouds using polarized lenses.</p><p>Since the clouds were expected to polarize the light that bounces off of them, by configuring the telescopes to look for this kind of light the clouds were much easier to spot. What the scientists observed, polarized light in patterns that extended outside the view of the telescope lens, was in line with the predictions of their mathematical model and ruled out other possible sources. </p>
Why are we just learning this now?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODgyMDAzOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2MjUyNDMyMH0.Zl8GmQ_rJHiL4b7hN0r_YBmgb6_ZqIRvqOVuko2ubpw/img.jpg?width=1245&coordinates=0%2C141%2C0%2C185&height=700" id="87afe" class="rm-shortcode" data-rm-shortcode-id="dd4c0b5088e601d7279cc5eb226f8b7b" data-rm-shortcode-name="rebelmouse-image" />
"Mosaic pattern of the angle of polarization around the L5 point (white dot) of the Earth-Moon system. The five rectangular windows correspond to the imaging telescope with which the patterns of the Kordylewski cloud were measured."
J. Slíz-Balogh<p>The objects, being dust clouds, are very faint and hard to see. While Kordylewski observed them in 1961, other astronomers have looked there and given mixed reports over the following decades. This discouraged many astronomers from joining the search, as study co-author Judit Slíz-Balogh <a href="https://ras.ac.uk/news-and-press/research-highlights/earths-dust-cloud-satellites-confirmed" target="_blank">explained</a>, <em>"The Kordylewski clouds are two of the toughest objects to find, and though they are as close to Earth as the Moon are largely overlooked by researchers in astronomy. It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbor."</em></p>
Will this have any impact on space travel?<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="c3d797fff5430c64afcb5a49bddc3616"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/Ou8N3v9SFPE?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Lagrange points have been put forward as excellent locations for a space station or satellites like the <a href="https://jwst.nasa.gov/about.html" target="_blank">James Webb Telescope</a> to be put into orbit, as they would require little fuel to stay in place. Knowing about a massive dust cloud that could damage sensitive equipment already being there could save money and lives in the future. While we only know about the clouds at Lagrange points four and five right now, the study's authors suggest there could be more at the other points.</p><p>While the discovery of a couple of dust clouds might not seem all that impressive, it is the result of a half-century of astronomical and mathematical work and reminds us that wonders are still hidden in our cosmic backyard. While you might never need to worry about these clouds again, there is nothing wrong with looking at the sky with wonder at the strange and fantastic things we can discover. </p>
New cancer-scanning technology reveals a previously unknown detail of human anatomy.
- Scientists using new scanning technology and hunting for prostate tumors get a surprise.
- Behind the nasopharynx is a set of salivary glands that no one knew about.
- Finding the glands may allow for more complication-free radiation therapies.
PSMA PET/CT technology<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="676e611b970c9b516cace0870447b325"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/RHAyoQF09X4?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>PSMA PET/CT is a new combination of <a href="https://www.mayoclinic.org/tests-procedures/pet-scan/about/pac-20385078" target="_blank">PET scans</a> and <a href="https://www.mayoclinic.org/tests-procedures/ct-scan/about/pac-20393675" target="_blank">CT scans</a> that is believed to offer a more reliable means of locating prostate cancer metastasis. A <a href="https://www.cancer.gov/news-events/cancer-currents-blog/2020/prostate-cancer-psma-pet-ct-metastasis" target="_blank" rel="noopener noreferrer">study</a> published last spring suggests it may be the most accurate way to diagnose prostate cancer metastasis than any method previously available.</p><p>Prior to PSMA PET/CT, the primary way to look for metastatic prostate cancer was to image the body using x-ray-based CT scans and to perform bone scans, since bone is where prostate cancer often spreads. CT scans, however, often miss small tumors, and bone scans can generate false positives as a result of other damage or abnormalities that have nothing to do with prostate cancer.</p><p>PSMA PET/CT scans track the travels of an intravenously administered radioactive glucose tracer throughout the body. For hunting down prostate cancer, this tracer contains a molecule that binds to the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1472940/" target="_blank">PSMA</a> protein that's present in large amounts in prostate tumors. The molecule is linked to a radioisotope, <a href="https://netrf.org/2018/11/13/gallium-68-scan-for-neuroendocrine-tumors/" target="_blank" rel="noopener noreferrer">gallium-68</a> (Ga-68).</p><p>In last spring's research, PSAM PET/CT was shown to be 27 percent more accurate than previous methods at finding metastases (92 percent accuracy as opposed to 65 percent). In addition, it was found to be much less likely to produce false positives, and it was particularly good at detecting tumors far removed from the prostate.</p>
A good kind of avoidance behavior<p>"Radiation therapy can damage the salivary glands," says Vogel, "which may lead to complications. Patients may have trouble eating, swallowing, or speaking, which can be a real burden."</p><p>The researchers looked back through the cases of 723 patients who had undergone radiation treatment, interested in seeing if inadvertent radiation of the tubarial glands was associated with the complications experienced by the patients. It turned out that this <em>was</em> the case: In cases where more radiation had been delivered to this area, patients did indeed report more in the way of complications of the type one would expect when salivary glands are radiated.</p><p>Now that we know the tubarial salivary glands exist, therapists can stay out of their way. Vogel says, "For most patients, it should technically be possible to avoid delivering radiation to this newly discovered location of the salivary gland system in the same way we try to spare known glands."</p><p>He's hopeful that that things may be about to get at least a bit better for cancer patients: "Our next step is to find out how we can best spare these new glands and in which patients. If we can do this, patients may experience less side effects which will benefit their overall quality of life after treatment."</p>
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