The mystery of moving, mossy, ‘glacier mice’

Atop certain glaciers are herds of small mossy balls that somehow move together when no one's looking.

Image source: Carsten ten Brink/flickr
  • Weird but cute, "glacier mice" are actually balls of moss, dirt, and more.
  • The balls move, oddly, in packs through some unknown means.
  • A new study tracked 30 glacier mice but still couldn't figure out what's going on.

Scientists have known about them at least since the 1950s, when Jón Eythórsson named them "jökla-mýs," which translates as "glacier mice." However, they're not actually mice. They're smallish balls of moss, and there are lots of them atop Alaska's Root Glacier. They can also be found on ice in Iceland, Svablard, and even South America, presumably places with just the right conditions, though researchers don't know what those conditions are.

The really odd thing about them is that they apparently move in some unexplained way, though no one has observed them doing so. It's just that repeated visits find them in different places.

And that's not the coolest part. "The whole colony of moss balls, this whole grouping, moves at about the same speeds and in the same directions," geologist Tim Bartholomaus of University of Idaho (UI) tells NPR. "Those speeds and directions can change over the course of weeks."

Bartholomaus and two colleagues have published their research on glacier mice in Polar Biology.

Mice but not mice

Image source: Steve Coulson/ The University Center at Svalbard

The "glacier mice" nickname has stuck perhaps because glaciologists are so fond of the fuzzy things. They are pillow-like, soft, squeezable objects, comprised of different species of moss, but that is not all.

A 2012 study found entire thriving habitats inside the mice. "I had expected to find some animals, but not so many," said study author and arctic biologist Steve Coulsonto to the New York Times. His research revealed springtails (six-legged insects), tardigrades (of course), and simple nematode worms. In a single mouse, there were 73 springtails, 200 tardigrades, and 1,000 nematodes.

Co-author of the new study, wildlife biologist Sophie Gilbert of UI describes them:

"They really do look like little mammals, little mice or chipmunks or rats or something running around on the glacier, although they run in obviously very slow motion."

Clues and an unsolved mystery

Some glacier mice are found perched on ice pedestals.

Image source: Fanny Dommanget/The University Center at Svalbard

Her report recounts the efforts made by Bartholomaus and his co-authors, which also included biologist Scott Hotaling of Washington State University, to figure out how the mice are getting around.

The 2012 study outfitted some mice with accelerometers and confirmed that they do rotate, but that's as far as its authors went into the balls' means of travel.

For Bartholomaus and his cohorts, there were some clues going into this.

For example, occasionally, balls are found perched on a pedestal of ice as seen above, perhaps shading that spot from melting sunlight until it finally melts and the ball rolls away.

Another clue is the intact nature of the healthy moss that serves as each ball's surface — it's a sign that they all have their turn in the sun. "These things must actually roll around or else that moss on the bottom would die," says Gilbert.

One obvious explanation was quickly ruled out — they're not simply rolling downhill, because many of them were found to be on level surfaces.

For the study, the researchers tagged 30 of the mice with a loop of wire and colored beads that identified each ball. They tracked their position for 54 days in 2009, and again in 2010, 2011, and 2012.

Bartholomaus explains, "By coming back year after year, we could figure out that these individual moss balls were living at least, you know, five, six years and potentially much, much longer."

Although the researchers expect the movements of the balls would be individualized and random, that's not what they found. The balls moved about an inch a day, and together, like a herd of animals.

Also, they periodically changed direction. "When we visited them all, they were all just sort of moving relatively slowly and initially toward the south," Bartholomaus said. "Then they all started to speed up and kind of start to deviate toward the west. And then they slowed down again and progressed even farther to the west."

Wind, maybe? Measurements of the dominant winds in the area ruled that out. Sunlight patterns also failed to account for the movement of the packs.

So, what's going on? Admits Barholomaus, "We still don't know. I'm still kind of baffled."

Suggestions

Given scientists' affection for the little balls, other people are also rolling the idea around in their minds. Ruth Mottram of the Danish Meteorological Institute suggests to NPR, "I think that probably the explanation is somewhere in the physics of the energy and the heat around the surface of the glacier, but we haven't quite got there yet."

Another theory put forward is that the moss on a ball's underside grows and pushes it over and forward, cueing up the next moss to begin growing in the same way. If growth rates from ball to ball are similar, this could explain their herd-like movement.

The mystery is reminiscent of the "sailing stones" of Death Valley that perplexed scientists for years unit their secret was revealed: They're pushed around by the wind as they temporarily float on wet melting ground ice.

A landslide is imminent and so is its tsunami

An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

Image source: Christian Zimmerman/USGS/Big Think
  • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
  • A wall of rock exposed by a receding glacier is about crash into the waters below.
  • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

The Barry Arm Fjord

Camping on the fjord's Black Sand Beach

Image source: Matt Zimmerman

The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

Not Alaska’s first watery rodeo, but likely the biggest

Image source: whrc.org

There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

The Barry Arm event will be larger than either of these by far.

"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

What the letter predicts for Barry Arm Fjord

Moving slowly at first...

Image source: whrc.org

"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

How do you prepare for something like this?

Image source: whrc.org

The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

North Atlantic Current could stop within the next century

New research suggests the ocean current that delivers warm water to Europe has a one-in-six chance of halting temporarily over the next hundred years, potentially resulting in freezing temperatures.

Tim Graham/Getty Images
  • The Atlantic Meridional Overturning Circulation, or AMOC, delivers warm water from the Gulf of Mexico to Europe, stabilizing its climate.
  • Increasing rainfall and glacial meltwater could seriously disrupt the current, which has been slowing down for the past 150 years.
  • Not all of the effects of an AMOC shutdown are clear, but it is likely that Europe will begin to see far colder winters should the current cease.

Despite its frequent rain and cloudy skies, the weather in London rarely dips into the truly miserable. In the wintertime, London is, at its coldest, only 5°C (41°F). During the summertime, it doesn't typically get much hotter than 23°C (74.5°F). Yet, if we were to travel westward, we'd arrive in the far chillier Newfoundland.

The reason why London enjoys such regular temperatures while Canadian cities that are equally as far north are forced to shiver in the cold has to do with ocean currents—specifically, the Atlantic Meridional Overturning Circulation, or AMOC. The portion of AMOC that most are probably familiar with is called the Gulf Stream, or the North Atlantic Current.

This massive current transports warm water from the Gulf of Mexico towards Europe, stabilizing much of northwestern Europe's climate.

"The oceans store an immense amount of energy and the ocean currents have a strong effect on the Earth's climate," said University of Groningen mathematician Fred Wubs in a statement.

However, human-driven changes to the climate are changing how oceans store energy. Correspondingly, this could change how AMOC functions. Modeling the impact of meltwater from Greenland and excessive rainfall, Wubs and his colleagues discovered that this current could temporarily halt within the 100 years, significantly impacting Europe's weather in the process.

More ice-skating on the Thames

AMOC

A topographic map of a portion of the Atlantic meridional overturning circulation depicting the circulation of surface currents (solid curves) and deep currents (dashed curves). Colors of curves indicate approximate temperatures.

R. Curry, Woods Hole Oceanographic Institution/Science/USGCRP

The AMOC has been weakening for the past 150 years and is currently at its weakest point of the past 1,500 years. This has spurred researchers to assess the current's future. Concerns over a complete failure of the AMOC inspired the 2004 film The Day After Tomorrow — although the events that took place in that film are clearly hyperbole.

Wubs and colleagues calculated that the possibility of a temporary shutdown of AMOC stood at 15 percent over the next 100 years, a one-in-six chance. Fortunately, however, the same model predicted that there was virtually no chance of a complete shutdown over the next 1,000 years.

For North America and Europe, this would mean colder winters, as well as hotter summers in Europe. More worryingly, this would also reduce the ocean's ability to absorb carbon dioxide, exacerbating the effects of climate change.

The AMOC has fluctuated over Earth's history, and when it has slowed down stopped in the past, massive cooling events typically followed. For instance, an AMOC slowdown has been implicated in the rise of the Little Ice Age, a period between 1200 and 1850 when temperatures in Europe dipped by about 1°C. Some researchers suggest that the Younger Dryas, an abrupt cooling period that took place between 12,900 and 11,7000 BP, occurred in part due to a change in AMOC, dropping the Earth's climate by 2 to 6°C in a matter of decades.

While the exact impacts of a temporary shutdown, especially under modern climate conditions, aren't entirely clear, such a shutdown would definitely spell colder winters for Europe. "Previous studies have shown that a shutdown of the AMOC would considerably affect the climate of the North Atlantic, and, more in general, of the Northern Hemisphere: the temperatures may drop by a few degrees, depending on the location," co-author Daniele Castellana told Newsweek. Their findings "strongly depend on the background state of the climate," he added.

It's important to note that even though an AMOC slowdown or shutdown will cool much of the northern hemisphere, higher levels of greenhouse gases in the atmosphere will still result in higher global temperatures over the long term. In fact, one study even suggested that an AMOC shutdown could result in extremely rapid increases in global temperatures, since the churning ocean current would be less able to store heat in the deep ocean, releasing it onto the surface instead.

If anything, recent findings into the AMOC's role in the global climate underscore just how large and complicated the Earth's systems really are. The AMOC has only been continuously monitored since 2004, so more research is needed before we can definitively say what is happening to it and what a temporary shutdown would mean for the rest of the world.

Ice sheet collapse: The greatest unknown in climate science

The ice sheets in Greenland and Antarctica are remnants of the ice age. They're also the wild cards of climate science.

  • The science of glaciology and ice sheets is quite new, as methods to measure melting glaciers were only realized with the advent of aviation and lasers.
  • The world's sea levels are rising 3mm per year, and of that Greenland's ice sheet contributes 1mm – it is losing between 250 to 300 billion tons of ice per year. Three millimeters total is not much, but ice sheets don't always operate in a linear fashion.
  • No human has ever witnessed an ice sheet collapse. It is also such a rare event that models cannot accurately predict what the effect will be. Can we halt global warming before we reach that tipping point?
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Greenland’s ice: A trip back in time to see the future of climate change

There are clues to the future and past trapped in Greenland's ice.

  • The Greenland ice sheet covers 80% of the island of Greenland. The sheet is 1,500 miles long, 700 miles across, and two miles thick. Scientists call it the largest laboratory in the world.
  • By studying the minerals and gasses trapped in layers of ice, glaciologists can unravel mysteries of the past, such as what the temperature was 1,000 years ago, or search for clues as to why the Greenland Norse people vanished.
  • Ice cores are a key to the past that also unlocks the future. Studying Greenland's ice sheet is yielding valuable information about the future of climate change.
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