Giant cave crystals may be home to 50,000-year-old microbes | Science News for Students

Giant cave crystals may be home to 50,000-year-old microbes

Finding hints that life might survive similarly extreme conditions on other planets
Mar 1, 2017 — 12:10 pm EST
cave microbes and crystals

Microbes were found in the fluid pockets of enormous crystals within Mexico's Naica mine. The germs may have been trapped in these minerals for up to 50,000 years.

ALEXANDER VAN DRIESSCHE/WIKIMEDIA COMMONS (CC BY 3.0)

BOSTON, Mass. — Scientists have turned up truly ancient microbes. They extracted them from giant cave crystals in Mexico. The stowaways may have survived there, unseen, for tens of thousands of years, new data indicate. Vastly different from nearly all other life-forms known, these germs offer a good indication of how resilient life can be in extremely harsh environments — even, potentially, conditions on other worlds.

“These organisms are so extraordinary,” says Penelope Boston. She is the director of NASA’s Astrobiology Institute in Moffett Field, Calif. 

Boston spoke here during a February 17 news conference at the annual meeting of the American Association for the Advancement of Science. The microbes she described are not closely related to any known genus, she said. Some of their closest relatives live in caves halfway around the world. Others make their homes in volcanic soils or thrive on toxic chemicals, such as toluene (TAHL-you-een).

Full of lead, silver and zinc, the Naica Mine is in Chihuahua, Mexico. For eight years, Boston was part of a team probing microbes there. The crystal  stowaways they turned up had been in  fluid pockets  inside massive crystals of calcium sulfate.

One might think of these microbes as having been tucked away in a time capsule for 10,000 to 50,000 years. They weren’t dead, just in suspended animation — perhaps for the entire time. They “remained viable,” Boston reports. In the lab, her team woke them up and studied their genetic material. The scientists also probed the genetic material in microbes on walls of the cave and elsewhere near the crystals.

Microbes from inside the crystals appear similar to — but not quite the same as — those on the cave walls and nearby areas, Boston says. Her team also thinks its age estimates for the crystal-trapped microbes are solid.

The new findings have not yet been published in a scientific journal. But if confirmed, these microbes would represent some of the toughest extremophiles (Ex-TREE-moh-files) on Earth. These are organisms that live in extreme conditions. They might come from where it’s extremely hot, such as near a volcano. Others may live in the ocean’s great depths or in around toxic chemicals. The Naica Mine microbes came from 100 to 400 meters (330 to 1,300 feet) below Earth’s surface. Temperatures there run 45° to 65° Celsius (110° to 150° Fahrenheit).

The new data show that microbes can be quite hardy. Almost any habitat can nurture some type of microbe. And that’s promising news in the hunt for life beyond Earth. It means that for life to exist on some distant planet, the conditions there may not have to match those on Earth.

Researchers are starting to plan probes to other worlds. These include Jupiter’s moon Europa and Saturn’s moon Enceladus. The new discovery in Mexico is a reminder of how little scientists know about the range of microbes that make their home on Earth. What scientists do not want is to risk that any of them might stow aboard a spacecraft sent to space, notes Cassie Conley. She’s NASA’s planetary protection officer. It’s her job to make sure that Earth’s microbes don’t contaminate other planets.

“If you took some of these organisms from Earth and put them elsewhere, they may do just fine,” she explains. That means Earth’s germs could one day end up living on — and polluting — other worlds.

Power Words

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astrobiology     The study of life everywhere in the universe, including on Earth and in space.

calcium     A chemical element which is common in minerals of the Earth’s crust and in sea salt. It is also found in bone mineral and teeth, and can play a role in the movement of certain substances into and out of cells.

crystal     (adj. crystalline) A solid consisting of a symmetrical, ordered, three-dimensional arrangement of atoms or molecules. It’s the organized structure taken by most minerals. Apatite, for example, forms six-sided crystals. The mineral crystals that make up rock are usually too small to be seen with the unaided eye.

dormant     Inactive to the point where normal body functions are suspended or slowed down.

Enceladus     The sixth largest of Saturn’s more than 50 moons. Enceladus is bright white and covered with a thick shell of ice. Deep beneath that ice sits what appears to be a global ocean of salty liquid water. Enceladus is a round sphere, 500 kilometers (310 miles) across. It is a little less than one-third the width of Earth's moon.

environment     The sum of all of the things that exist around some organism or the process and the condition those things create for that organism or process. Environment may refer to the weather and ecosystem in which some animal lives, or, perhaps, the temperature, humidity and placement of components in some electronics system or product.

Europa     One of the moons of Jupiter and the sixth-closest satellite to the planet. Europa, 1,951 miles across, has a network of dark lines on a bright, icy surface.

extremophile     A microorganism that lives in conditions of extreme temperature, acidity, alkalinity or chemical concentration.

genetic     Having to do with chromosomes, DNA and the genes contained within DNA. The field of science dealing with these biological instructions is known as genetics. People who work in this field are geneticists.

genus     (plural: genera) A group of closely related species. For example, the genus Canis — which is Latin for “dog” — includes all domestic breeds of dog and their closest wild relatives, including wolves, coyotes, jackals and dingoes.

habitable     A place suitable for humans or other living things to comfortably dwell.

habitat     The area or natural environment in which an animal or plant normally lives, such as a desert, coral reef or freshwater lake. A habitat can be home to thousands of different species.

journal     (in science) A publication in which scientists share their research findings with the public. Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send out all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.

Jupiter     (in astronomy) The solar system’s largest planet, it has the shortest day length (10 hours). A gas giant, its low density indicates that this planet is composed of light elements, such as hydrogen and helium. This planet also releases more heat than it receives from the sun as gravity compresses its mass (and slowly shrinks the planet).

lead     A toxic heavy metal (abbreviated as Pb) that in the body moves to where calcium wants to go. The metal is particularly toxic to the brain, where in a child’s developing brain it can permanently impair IQ, even at relatively low levels.

microbe     Short for microorganism. A living thing that is too small to see with the unaided eye, including bacteria, some fungi and many other organisms such as amoebas. Most consist of a single cell.

moon     The natural satellite of any planet.

NASA     Short for the National Aeronautics and Space Administration. Created in 1958, this U.S. agency has become a leader in space research and in stimulating public interest in space exploration. It was through NASA that the United States sent people into orbit and ultimately to the moon. It has also sent research craft to study planets and other celestial objects in our solar system.

organism     Any living thing, from elephants and plants to bacteria and other types of single-celled life.

planet     A celestial object that orbits a star, is big enough for gravity to have squashed it into a roundish ball and it must have cleared other objects out of the way in its orbital neighborhood. To accomplish the third feat, it must be big enough to pull neighboring objects into the planet itself or to sling-shot them around the planet and off into outer space. Astronomers of the International Astronomical Union (IAU) created this three-part scientific definition of a planet in August 2006 to determine Pluto’s status. Based on that definition, IAU ruled that Pluto did not qualify. The solar system now includes eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Saturn     The sixth planet out from the sun in our solar system. One of the four gas giants, this planet takes 10.7 hours to rotate (completing a day) and 29 Earth years to complete one orbit of the sun. It has at least 53 known moons and 9 more candidates awaiting confirmation. But what most distinguishes this planet is the broad and flat plane of seven rings that orbit it.

sulfate     A family of chemical compounds that are related to sulfuric acid (H2SO4). Sulfates occur naturally in drinking water.

viable     (in biology) Able to survive and/or live a normal lifespan. (in engineering) Something that should work or operate according to plan, as in a “viable concept.”

Citation

Meeting:​​ ​ P. Boston. “The astrobiological exploration of Earth and Mars.” American Association for the Advancement of Science annual meeting. Boston, February 17, 2017.