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5 Extreme Life-Forms That Live on the Edge

By Liz Langley We humans think we’re pretty hot stuff—but that depends on what you’re measuring. When it comes to enduring harsh conditions, for example, there are creatures in this world that make us look like a bunch of cupcakes. Meet the extremophiles, so-called because they can withstand environments so intensely hot, cold, salty, acidic,...

By Liz Langley

We humans think we’re pretty hot stuff—but that depends on what you’re measuring. When it comes to enduring harsh conditions, for example, there are creatures in this world that make us look like a bunch of cupcakes.

Meet the extremophiles, so-called because they can withstand environments so intensely hot, cold, salty, acidic, alkaline, pressurized, dry, radioactive, or barren they’d put us out like a match in a hurricane. So impressive are their superpowers that NASA made them trading cards, just like Superman.

tardigrade picture
It may look like a bear, but it’s actually a millimeter long. Photograph by Eye of Science, Science Source

Extremophiles not only do exceptional things, they’ve opened our minds about what life is and what kind of environments can support it, widening our view of the potential for life on other planets, scientists say.

“People who work with extremophiles have pretty much the same needs as people who are going to Mars except they can usually be there to operate the instruments themselves; they don’t have to have a robot do it. But it terms of technology and techniques it’s really the same,” said Jay Nadeau, associate professor of biomedical engineering at McGill University who studies extremophilic bacteria in the Canadian Arctic.

Her team was the first to describe the microbe genus Thiomicrospirawhich has slight modifications to its cell structure that allow it thrive in its icy home.

Extremophiles could also help us with more earthly concerns, from pharmaceuticals to producing energy, but, Nadeau said, “A lot of this work is really done just for the interest in finding out what there is on planet Earth that we don’t know about … and there’s a lot of that.”

Bonus: Some of them are just plum adorable. Here are five of the coolest extremophiles.

Tardigrades and Tiaras

No question—if there were a cute extremophile contest, the tardigrade (above) would win. They even have a cute a nickname—“water bear”—and look like manatees dressed in spacesuits for Halloween.

Measuring about a millimeter long, the tardigrade is a polyextremophile, which means its capable of surviving numerous harsh conditions. Sarah Bordenstein of the Marine Biological Laboratory at Woods Hole writes that they can withstand temperatures from  -328 °F (200 °C) up to 304 °F (151 °C), lack of water and oxygen, “boiling alcohol,” (who thought of that?) and a thousand times the radiation we can take.

One way they survive is by going into cryptobiosis, a state of suspended animation, in which body functions like metabolism temporarily shut down. They’ll stay in this shrunken state—in which they’re called a “tun”—until conditions improve.  They have been known to do this for decades.

Understandably, the tardigrade has become sort of a pop/nerd culture darling, with its adorable mug appearing on everything from own t-shirts to mouse pads to, well, mugs.

No, we don’t have a number for their agent.

Brine Shrimp: Salty Survivors

Those of us who could eat popcorn, chips, and salty snacks until we pop can easily identify with the halophile, a creature that thrives in very salty environments. The Great Salt Lake brine shrimp are halophiles that are at home in places like the Great Salt Lake of Utah, parts of which are ten times saltier than the ocean.

brine shrimp picture
A brine shrimp up close. Photograph by 3QuarksMedia

Brine shrimp are such super salty survivors because, according to the Great Salt Lake Ecosystem Program,  their outer body is impermeable to water so the salt water only enters through the mouth. Two pumps, the shrimp’s gills and a special neck gland, filter the salt out and help keep a salt balance in the body.

They also have three types of hemoglobin, a protein that binds oxygen in the blood. Hemoglobin levels increase in the shrimp when the water’s salinity increases.

Methane Ice Worm

They may look alien, but the hideous creature pictured below is a methane ice worm, discovered here on Earth in 1997, living on the sea floor of the Gulf of Mexico. These extremophilic flat, pinkish, up-to-two-inch-long worms were found burrowing into mounds of methane and likely living on the bacteria that grow on the methane.

methane ice worm picture
No, it’s not an alien—it’s a methane ice worm. Photograph courtesy NOAA

In fairness if you looked like that you’d burrow, too.

Considerably less ghastly are glacial ice worms, squiggly black creatures a few centimeters long. Daniel Shain, biology department chair at Rutgers-Camden, has sought out ice worms in far flung places places from Tibet to Alaska—partly funded by National Geographic. (Watch a video of the ice worms in Alaska.)

Reporting on a hike lead by Shain, Doug O’Harr of the Anchorage Daily News reported seeing so many worms that one glacier appeared to have “sprouted sparse hair.”

Glacial ice worms are “the largest animal known to complete its life cycle on glacier ice, which is quite a feat,” Dan wrote in an email.

They survive on algae and are similar to earth worms but their body functions—reproduction, metabolism, growth—all occur at the freezing mark, at about 32° Fahrenheit (0° Celsius). If temperatures go up a few degrees, though, to about 40° Fahrenheit (4° Celsius), the worms can’t take it—they eventually melt and die.

Which shows that our idea of “extreme” is relative.

“Rushing Fireball” Microbe

In some images,  Pyrococcus furiosus looks like an abstract drawing of a Fantasia goldfish, in others like butterscotch candy left in the dish a little too long. In real life this tough little anaerobe, whose name means “rushing fireball,” prefers water temperatures at the boiling point: 212° Fahrenheit (1000° Celsius), which makes it a hyperthermophile. Thermophiles like it hot; hyperthermophiles would pick hell for vacation.

Karl Stetter discovered P. furiosus in the geothermally heated marine sediments in Italy’s Vulcano Islands in the 1980s. (See more pictures of marine microbes.)

Russell McLendon of Mother Earth News reported this spring that scientists at the University of Georgia have been diddling around in the fireball’s genes, creating a version of the microbe that prefers cooler climates and has a taste for carbon dioxide rather than its usual carbs. The hope is to create a variant of the fireball that breathes in carbon dioxide and turns it into fuel.

When that’s done we’d like a cat that breathes in anger and turns it into donuts. Science? Anyone?

Radiation-Resistant Bacteria

Beautiful, resilient, mysterious … all the qualities of a film noir heroine locked are wrapped in this bacteria Dienococcus radiodurans, which looks—at least in this image—like a changing mood ring.

The Genome News Network says it was discovered “nearly fifty years ago in a can of ground meat that spoiled despite having been sterilized by radiation,” and that resistance to radiation is the prize-winning talent of this polyextremophile. When it’s genome is broken down by radiation, D. radiodurans just stitches it back together perfectly—and pretty quickly—and keeps going.

The Lazurus microbe, as it’s been called, holds the Guinness World Records title for “Most Radiation Resistant Life-Form“—it can withstand about 3,000 times as much radiation as we can. And it’s a one-celled organism.

This makes it of great interest to scientists: Figuring out how the microbes resist radiation may give insight into protecting people from various types of radiation exposure, from chemotherapy to sun damage.

So … what did you do today?

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