The Science Behind Antarctica's Blood Falls

In 1911, a geologist on the ultimately doomed Terra Nova expedition to the South Pole discovered a five-story-tall, blood-red waterfall in the middle of the frozen Antarctic desert lands. The area, known as the McMurdo Dry Valleys, is the largest ice-free region on the continent, and one of the coldest, driest, most Mars-like places on Earth.

The so-called Blood Falls ooze from a crack in Taylor Glacier onto the ice-covered Lake Bonney. Twice as salty as seawater, the red brine never freezes. But why is it so red? It's because of the extremely rich presence of iron in the water, which oxidizes and turns crimson when exposed to air, as a research team led by microbiologist Jill Mikucki discovered in 2009. The team also identified 17 microorganisms in the surface brine. Before then, scientists thought a type of algae might be responsible for the red hue.

Image Credit: Peter Rejcek, National Science Foundation

More recent research by Mikucki, published in Nature Communications, discovered that the source of Blood Falls is a subglacial lake. They conducted the first-ever landscape-scale survey of subsurface resistivity in Antarctica. They mapped the region using a large airborne electromagnetic (AEM) system called SkyTEM, which was flown via helicopter. As Smithsonian notes, when water freezes, it has higher electrical resistivity. Salt-rich brine, on the other hand, has low resistivity.

You can see a short video of the AEM system here:

According to New Scientist, the sensor detected a 185-meter-long lake beneath the surface near Blood Falls. Nearly devoid of oxygen and trapped a quarter-mile down for 2 million years, the lake nevertheless harbors life, which appears to use sulfate instead of oxygen for respiration. Because the researchers detected large regions of low electrical resistivity beneath the surface, they believe the lake is one of two extensive subsurface brine systems.

As Mikucki told the Washington Post, "We found, as expected, that there was something sourcing Blood Falls…and we found that these brines were more widespread than previously thought. They appear to connect these surface lakes that appear separated on the ground. That means there's the potential for a much more extensive subsurface ecosystem, which I'm pretty jazzed about."

This is one conceptualization of how the subglacial lakes may connect beneath the surface of the forbidding region:

 

 

Image Credit: J.A. Mikuckiin, in Nature Communications

'Lost Species' of Tiny, Rabbit-Sized Deer Photographed in Vietnam for the First Time in 30 Years

Global Wildlife Conservation
Global Wildlife Conservation

The silver-backed chevrotain, also called the Vietnamese mouse-deer, is elusive. It's so elusive that scientists had feared it was extinct after none had been photographed for decades. But as The Washington Post reports, the first images taken of the mammal in nearly 30 years prove that the species is still alive in the woods of Vietnam.

No larger than small dogs, chevrotains are the tiniest ungulates, or hoofed animals, on Earth. They have vampire-like fangs and skinny legs that support their bodies. Silver-backed chevrotains are characterized by the silver sheen of their tawny coat.

The tiny population native to Vietnam has been devastated by poachers in recent decades. That, and the animal's natural shyness, make it incredibly difficult to study. Before this most recent sighting, the last time scientists had recorded one was in 1990.

Global Wildlife Conservation, the Southern Institute of Ecology, and the Leibniz Institute for Zoo and Wildlife Research teamed up in hopes of documenting the lost species. Researchers interviewed residents and government forest rangers in the Vietnamese city of Nha Trang about the silver-backed chevrotain, looking for tips on where to find one. Residents said that while populations had been hit hard by hunting, the animals were still around.

Based on this local ecological knowledge, scientists set up three camera traps in the Vietnamese woods. In just five months, they captured 275 photographs of the little mouse-deer. They then installed 29 additional cameras and snapped 1881 new images in that same length of time.

“For so long this species has seemingly only existed as part of our imagination," Global Wildlife Conservation associate conservation scientist An Nguyen said in a statement. "Discovering that it is, indeed, still out there, is the first step in ensuring we don’t lose it again, and we’re moving quickly now to figure out how best to protect it.”

Now that a silver-backed chevrotain population has been located, researchers plan to conduct the first-ever comprehensive survey of the species. Once the data is collected, it will be used to build a plan for the species' survival.

[h/t The Washington Post]

The Great Tryptophan Lie: Eating Turkey Does Not Make You Tired

H. Armstrong Roberts/iStock via Getty Images
H. Armstrong Roberts/iStock via Getty Images

While you’re battling your cousins for the best napping spot after Thanksgiving dinner, feel free to use this as a diversion tactic: It’s a myth that eating turkey makes you tired.

It’s true that turkey contains L-Tryptophan, an amino acid involved in sleep. Your body uses it to produce a B vitamin called niacin, which generates the neurotransmitter serotonin, which yields the hormone melatonin, which helps regulate your sleeping patterns. However, plenty of other common foods contain comparable levels of tryptophan, including other poultry, meat, cheese, yogurt, fish, and eggs.

Furthermore, in order for tryptophan to produce serotonin in your brain, it first has to make it across the blood-brain barrier, which many other amino acids are also trying to do. To give tryptophan a leg up in the competition, it needs the help of carbohydrates. Registered dietitian Elizabeth Somer tells WebMD that the best way to boost serotonin is to eat a small, all-carbohydrate snack a little while after you’ve eaten something that contains tryptophan, and the carbs will help ferry the tryptophan from your bloodstream to your brain.

But Thanksgiving isn’t exactly about eating small, well-timed snacks. It’s more about heaps of potatoes, mountains of stuffing, and generous globs of gravy—and that, along with alcohol, is more likely the reason you collapse into a spectacular food coma after your meal. Overeating (especially of foods high in fat) means your body has to work extra hard to digest everything. To get the job done, it redirects blood to the digestive system, leaving little energy for anything else. And since alcohol is a central nervous system depressant, it also slows down your brain and other organs.

In short, you can still hold turkey responsible for your Thanksgiving exhaustion, but you should make sure it knows it can share the blame with the homestyle mac and cheese, spiked apple cider, and second piece of pumpkin pie.

[h/t WebMD]

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