by Sarah Rush
Spring 2017 Intern
Have you heard of microscopic
animals called water bears? When I learned about these little guys a few years
ago, my idea of what life is capable of was turned upside down and inside out.
Also called tardigrades, water bears can survive extreme temperatures,
pressure, radiation and even
the vacuum of space! I’m fascinated by extremophiles— microorganisms that
can withstand unimaginably harsh conditions—and what their existence could mean
when we consider just how adaptive life can become.
Well, scientists have found yet
more mysterious and fascinating extremophiles
trapped inside enormous crystals. In Chihuahua, Mexico, there is a massive
cave system connected to the Naica Mine called the Cave
of Crystals. Named for its breathtaking selenite crystals (some have grown
up to 30 feet long!), the cave was discovered by miners in 2000 and sits above
a repository of magma. It’s exceedingly hot: it can reach up to 112 degrees
Fahrenheit with intense humidity. In 2008, Penelope Boston from NASA and her
team collected samples from fluids trapped in pockets within the giant
crystals, and in February 2017 she announced their discovery of new microbial specimens—nearly
100 new extremophiles, most of which have likely never been studied by
scientists before.
The creatures were found in a state
of geolatency,
trapped dormant inside geological materials (in this case, inside the crystals).
Boston’s team was able to revive a number of the microbes, and they believe they
could be anywhere from 10 thousand to 50 thousand years old! Scientists hypothesize that they
survived by consuming iron, sulfur and other traditionally inorganic material
inside the crystals, demonstrating that life may be more resilient and flexible
than we previously thought. Some even think the existence of extremophiles
makes it more likely that life could exist on other planets.
Other researchers are skeptical
about Boston’s conclusions, specifically those concerning exactly how old the microbes
are and whether possible contamination might have skewed the team’s results. Boston’s
findings have not been peer-reviewed, and some scientists speculate that it may
not be true that the microscopic organisms came solely from inside the crystal,
as it may be possible some were accidentally introduced during the extrication
process.
Another expedition into the Cave of
Crystals might provide more answers, but the mine has since closed and the cave
is now flooded with groundwater. Hopefully, a second look at these new
extremophiles might further illuminate life’s limitations . . . if there are any.
Did You Know?
The very center of Earth may
actually be made up of a massive conglomerate
of crystals! Scientists used data collected from seismic waves to determine
that Earth’s inner core—a solid region the size of the moon—may consist of two
huge chunks of iron crystals, each aligned in a different direction (some north
to south and others east to west).
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