Sunday October 21, 2018
Home Lead Story Scientists Th...

Scientists Think Microbes May be the Reason Behind Tunnels in Thai Garnets

The researchers argue that the microbes bored into the garnets while they were in the river bed. Microbes in the sediment of the river lack access to chemical energy sources like iron, which is contained in the garnet crystals.

0
//
40
thai-garnet
This image shows a garnet crystal with distinct tubular structures. VOA
Republish
Reprint

Life has found a way to survive in some of the most extreme conditions imaginable. Now, scientists believe they might have found a new habitat for hardy microbes — inside garnets.

New research found unusual patterns of tunnels in Thai garnets with deposits of fatty acids in the burrowed pathways, indicating a microbe caused the damage.

Magnus Ivarsson, lead researcher on the study at the University of Southern Denmark, said the research started with an exchange student from Thailand who was studying the gem quality of the garnets. She discovered the tunnels that branched and changed directions, unlike previously described environmental weathering, and consulted Ivarsson.

“When I first saw these structures, these tunnels, I was sort of intrigued by the complexity of them,” Ivarsson told VOA. “I have previously studied other microbial boring in minerals and materials, but I’ve never seen anything with this complexity.”

The garnets are an unexpected habitat for microbes because of their hardness. In fact, according to Ivarsson, this is the hardest mineral yet discovered to be bored by microbes.

“Who knows what we’ll find next. Maybe a diamond bored by microbes. Who knows?” Ivarsson said.

Researchers are careful to point out that no living organisms were discovered within the gemstones.

Dawn Cardace, a researcher in the department of geosciences at the University of Rhode Island, studies how geology and biology interact. She told VOA that while this study didn’t find any DNA of the organisms, “This wasn’t troubling to me, largely because they chose to work with the sample set they have at a very close, submicroscopic scale.” She said they would have needed at least a thousand gemstones in order to collect a DNA sample.

About the research

The researchers relied on several technologies to come to their conclusions.

First, the scientists used microscopy to make 3D maps of the tunnels on the scale of microns. A human hair is about 50 microns wide, but the tunnels in the garnets were generally smaller, hence the need for high-powered microscopes.

microbes
This image is a microphotograph of the network of tubular structures originating at the garnet’s surface. (Photo courtesy of Ivarsson et al, 2018). VOA

The scientists focused on how the tunnels spread and changed directions, and when they converged at crossing points called “anastomosis.” Although environmental weathering can cause cracks and fissures in hard minerals, Ivarsson said weathering processes can’t explain the complexity of the tunnels they observed.

The second step to demonstrate that microbes most likely created the tunnels required analyzing the interior of the boreholes.

“The organic content tells us that there’s been life living in there,” said Ivarsson.

In particular, they detected lipids and fatty acids, which are organic compounds common among bacteria and fungi.

Ivarsson and his colleagues compared these biological traces to hematite and quartz grains found in the same location as the garnets, in the river sediment of the Chiang Mai stream. Neither of the comparable stones showed signs of fatty acids, indicating the biological traces were unique to the garnet tunnels.

When asked about the results, Ivarsson said, “At this point we can say at least that biology has been involved. I would suggest that it’s fungi that has been involved in this. But at the same time, I think we should be really cautious because there might be other processes [at work] that are not known today.”

More studies needed

Cardace agrees that while microbes were certainly living inside the gemstones, further research is needed to prove how the tunnels were created. She said she would like future studies to show “a set of experiments done with candidate microorganisms that could do the metabolic work” the researchers proposed in their paper.

Ivarsson and his colleagues did, however, consider why microbes like fungi might be making the garnets their home. They sampled garnets from river sediment in Thailand, as well as within granite upstream.

Thai Garnet
Thai Garnet Jewelry. Flickr

Ivarsson told VOA, “When we studied these garnets in the granite, we could see that there were no tunnels. But when we looked at the garnets further down the river, we could see that these tunnels structures had evolved. So, something happened along the way, along the transport in the river system.”

The researchers argue that the microbes bored into the garnets while they were in the river bed. Microbes in the sediment of the river lack access to chemical energy sources like iron, which is contained in the garnet crystals. Perhaps, researchers propose, the microorganisms created the filaments within the gemstones to access this resource.

Monetary value

Such changes to the garnets, however, decrease the value of the stones.

Shane McClure, global director of colored stones at the Gemological Institute of America, told VOA that when it comes to determining the value of garnets, “If there’s only one or two [tunnels] and they’re very small, it doesn’t affect the value at all. But if there’s a whole bunch of them and they’re very visible, well then it’s going to affect it quite a bit from a gemstone perspective.”

These gemstones might not be usable for flashy jewelry, but they do demonstrate that life finds a way in all sorts of inhospitable and unexpected locations.

Also Read: Jewellery Trends For 2018

As Ivarsson told VOA, “When we look for life on Mars, we need to know what to look for. And this is one type of biological signature that is definitely interesting in the search for life on Mars or any type of extreme environment.” (VOA)

Click here for reuse options!
Copyright 2018 NewsGram

Next Story

Invasive Species May Not Be All Bad: Scientists

An active debate among biologists about the role of invasive species in a changing world is going on

0
Invasive Species
The invasive European green crab is tearing down ecosystems in Newfoundland and building them up on Cape Cod. VOA

Off the shores of Newfoundland, Canada, an ecosystem is unraveling at the hands (or pincers) of an invasive crab.

Some 1,500 kilometers (930 miles) to the south, the same invasive crab — the European green crab — is helping New England marshes rebuild.

Both cases are featured in a new study that shows how the impacts of these alien invaders are not always straightforward.

Around the world, invasive species are a major threat to many coastal ecosystems and the benefits they provide, from food to clean water. Attitudes among scientists are evolving, however, as more research demonstrates that they occasionally carry a hidden upside.

“It’s complicated,” said Christina Simkanin, a biologist at the Smithsonian Environmental Research Center, “which isn’t a super-satisfying answer if you want a direct, should we keep it or should we not? But it’s the reality.”

Simkanin co-authored a new study showing that on the whole, coastal ecosystems store more carbon when they are overrun by invasive species.

Good news, crab news

Take the contradictory case of the European green crab. These invaders were first spotted in Newfoundland in 2007. Since then, they have devastated eelgrass habitats, digging up native vegetation as they burrow for shelter or dig for prey. Eelgrass is down 50 percent in places the crabs have moved into. Some sites have suffered total collapse.

That’s been devastating for fish that spend their juvenile days among the seagrass. Where the invasive crabs have moved in, the total weight of fish is down tenfold.

The loss of eelgrass also means these underwater meadows soak up less planet-warming carbon dioxide from the atmosphere.

In Cape Cod, Massachusetts, the same crab is having the opposite impact.

Off the coast of New England, fishermen have caught too many striped bass and blue crabs. These species used to keep native crab populations in check. Without predators to hold them back, native crabs are devouring the marshes.

But the invasive European green crab pushes native crabs out of their burrows. Under pressure from the invader, native crabs are eating less marsh grass. Marshes are recovering, and their carbon storage capacity is growing with them.

Invasive species
In this May 8, 2016 photo, eelgrass grows in sediment at Lowell’s Cove in Harpswell, Maine. VOA

Carbon repositories

Simkanin and colleagues compiled these studies and more than 100 others to see whether the net impact on carbon storage has been positive or negative.

They found that the ones overtaken by invasive species held about 40 percent more carbon than intact habitats.

They were taken by surprise, she said, because “non-native species are thought of as being negative so often. And they do have detrimental impacts. But in this case, they seem to be storing carbon quicker.”

At the Smithsonian Environmental Research Center where she works, the invasive reed Phragmites has been steadily overtaking a marsh scientists are studying.

Phragmites grows much taller, denser and with deeper roots than the native marsh grass it overruns.

But those same traits that make it a powerful invader also mean it stores more carbon than native species.

“Phragmites has been referred to as a Jekyll and Hyde species,” she said.

Not all invaded ecosystems stored more carbon. Invaded seagrass habitats generally lost carbon, and mangroves were basically unchanged. But on balance, gains from marsh invaders outweighed the others.

Invasive species
Phragmites plants growing on Staten Island draft in a breeze in the Oakwood Beach neighborhood of Staten Island. VOA

Not a lot of generalities

To be clear, Simkanin said the study is not suggesting it’s always better to let the invaders take over; but, it reflects an active debate among biologists about the role of invasive species in a changing world.

“One of the difficult things in the field of invasion biology is, there aren’t a lot of generalities,” said Brown University conservation biologist Dov Sax, who was not involved with the research. “There’s a lot of nuance.”

The prevailing view among biologists is that non-native species should be presumed to be destructive unless proven otherwise.

When 19 biologists wrote an article in 2011 challenging that view, titled, “Don’t judge species on their origins,” it drew a forceful rebuke from 141 other experts.

Sax said the argument is likely to become more complicated in the future.

Also Read: Climate Change Not A Hoax: Trump

“In a changing world, with a rapidly changing climate, we do expect there to be lots of cases where natives will no longer be as successful in a region. And some of the non-natives might actually step in and play some of those ecosystem services roles that we might want,” he said.

“In that context, what do we do? I definitely don’t have all the answers.” (VOA)