NASA is famous for its exploration and discovery in space!
However, the agency is also making discoveries under the Earth, right here on the planet!
One of such is the strange new discovery under Antarctica's ice that changes the way scientists
have viewed the planet!
What has NASA discovered?
And does it affect you?
Join us as we dive into NASA's strange new discovery under Antarctica's ice!
Few people have Antarctica as their dream destination, and that is understandable!
Antarctica is the fifth-largest continent, covering about 5.4 million square miles or
14 million square kilometers.
However, the size varies through the seasons, as expanding sea ice along the coast nearly
doubles the continent's size in the winter.
Almost all of Antarctica is covered with ice; in fact, less than half a percent of the vast
wilderness is ice-free!
This place contains 90 percent of all of the ice on Earth in an area just under 1.5 times
the size of the United States!
The place is so cold that if you throw boiling water into the air, it will instantly vaporize
because most of the particles will turn into steam, while the rest is instantly converted
into small pieces of ice!
The continent is divided into two regions, known as East and West Antarctica.
East Antarctica makes up two-thirds of the continent and is about the size of Australia.
Ice in this part of the continent averages 1.2 miles or 2 kilometers thick.
West Antarctica is a series of frozen islands stretching toward the southern tip of South
America, forming an extension of the Andes Mountains.
The two regions are separated by the Transantarctic Mountains, which stretch across the continent
and are sometimes completely covered by ice.
Is there plant life in Antarctica?
Sort of!
It is limited to a smattering of mosses, lichen, and algae.
Seasonal moss coverage on Antarctica has increased steadily over the last 50 years.
However, animal life is much more abundant, despite the absence of amphibians, reptiles,
and terrestrial mammals.
There are large populations of penguins, whales, fish, and invertebrates thriving along Antarctica's
coasts and frigid seas, especially in the summer.
What about human life on this wide expanse of ice?
While there are no indigenous people in Antarctica, due to the harsh weather, you can find as
many as 4,000 visiting scientists spread out across 70 research stations, braving the cold
on the continent in the summer.
That number drops to 1,000 during the even harsher winter!
Antarctica is mainly a hub for climatologists, oceanographers, and marine biologists.
However, the frozen dessert also attracts astronomers from across the globe.
This is because, if you can bear the cold, Antarctica is one of the best places on Earth
to observe space!
This is thanks to its dry climate and the absence of light pollution.
Speaking of watching space, this brings NASA, the king of the outer universe, into the mix!
What has NASA been doing in Antarctica?
Looking down from the above, you might think the Antarctic Ice Sheet looks like a calm,
perpetual ice blanket that has covered Antarctica for millions of years.
But don't be surprised that the ice sheet can be thousands of meters deep at its thickest
and hides hundreds of meltwater lakes where its base meets the continent's bedrock!
Now, using the most advanced Earth-observing laser instrument NASA has ever flown in space,
scientists have improved their maps of these hidden lake systems under the West Antarctic
ice sheet, and have discovered two more of these active subglacial lakes, named Conway
and Mercer!
The new study provides critical insight for spotting new subglacial lakes from space and
assessing how this hidden plumbing system influences the speed at which ice slips into
the Southern Ocean, adding freshwater that may alter its circulation and ecosystems.
With NASA's Ice, Cloud, and land Elevation Satellite 2, or ICESat-2, scientists have
been able to precisely map the subglacial lakes.
The satellite measures the height of the ice surface, which, despite its enormous thickness,
rises or falls as lakes fill or empty under the ice sheet.
The study, published in Geophysical Research Letters, integrates height data from ICESat-2's
predecessor, the original ICESat mission, and the European Space Agency's satellite
dedicated to monitoring polar ice thickness, CryoSat-2.
Hydrology systems under the Antarctic ice sheet have been a mystery for decades.
That began to change in 2007, when Helen Amanda Fricker, a glaciologist at Scripps Institution
of Oceanography at the University of California San Diego, made a breakthrough that helped
update classical understanding of subglacial lakes in Antarctica.
Using data from the original ICESat in 2007, Fricker found for the first time that under
Antarctica's fast-flowing ice streams, an entire network of lakes connects, filling
and draining actively over time.
Before, these lakes were thought to hold meltwater statically, without filling and draining.
The original ICESat mission is credited with discovering the interconnected systems of
lakes at the ice-bed interface that are moving water around, allowing scientists to study
all the impacts on glaciology, microbiology, and oceanography.
However, with ICESat-2, scientists had a powerful tool that yielded data so high in precision
that they were able to start mapping out the lake boundaries on the surface!
Scientists have hypothesized subglacial water exchange in Antarctica results from a combination
of factors, including fluctuations in the pressure exerted by the massive weight of
the ice above, the friction between the bed of the ice sheet and the rocks beneath, and
heat coming up from the Earth below that is insulated by the thickness of the ice.
That's a stark contrast from the Greenland ice sheet, where lakes at the bed of the ice
fill with meltwater that has drained through cracks and holes on the surface.
How deep below the surface are the Conway and Mercer lakes?
These hidden gems of frigid water are hidden beneath 1.2 to 2.5 miles or 2 to 4 kilometers
of ice on the southernmost continent!
They fill and drain over and over again in largely mysterious cycles that may influence
how fast the ice sheet moves and how and where meltwater reaches the Southern Ocean.
This flow, in turn, can change the currents in the Southern Ocean and potentially affect
ocean circulation worldwide.
Unlike most lakes on the surface that remain in a place for years, this underground water
system is dynamic or highly fluid, pun intended!
By combining data from multiple satellites from 2003 to 2020, scientists have been able
to trace changes in the subglacial lake system between those years!
They focused on three areas with good satellite coverage and known active lakes: the boundary
between the Mercer and Whillans ice streams in West Antarctica; the lower MacAyeal Ice
Stream, also in West Antarctica; and the upper Academy Glacier in East Antarctica.
At the Mercer and Whillans boundary, the researchers found two new lakes, which they dubbed the
Lower Conway Subglacial Lake and the Lower Mercer Subglacial Lake.
They also found that what was thought to be one lake under the MacAyeal ice stream was
actually two.
Over time, these lakes experienced major change.
For example, the lakes beneath the Mercer and Whillans ice stream boundary have undergone
at least three periods of drainage in 17 years.
Meanwhile, all of the lakes beneath the MacAyeal ice stream have followed their own patterns
of draining and filling.
The lowermost lake went through four fill-drain events during the study period, each taking
only about a year to complete.
The second lake drained between 2014 and 2015 and had been filling up again, while the third
lake drained just slightly between 2016 and 2017.
Meanwhile, the lakes beneath Academy Glacier drained between 2009 and 2018.
All of these changes are puzzle pieces in scientists' understanding of the speed and
direction of Antarctica's ice sheet flow.
Already, researchers are finding the links between the under-ice lakes and the ocean:
In January last year, a study co-authored found that the drainage of one lake on the
Amery Ice Shelf in East Antarctica flushed as much as 198 billion gallons or 750 billion
liters into the ocean in only three days, as reported by Live Science!
While it is fascinating to find lakes buried deep underneath the ice in the Antarctic,
one question you might be asking is whether there is life in that lake!
The environment is harsh enough on the surface, but can life survive deep down in the two
newly discovered lakes?
Expedition leader John Priscu, a professor of polar ecology at the University of Montana,
answers that early studies of water samples taken from Lake Mercer showed that they contained
approximately 10,000 bacterial cells per milliliter!
While that is only about 1 percent of the 1 million microbial cells per milliliter typically
found in the open ocean, it remains a remarkable find for a sunless body of water buried deep
beneath an Antarctic glacier!
But that is not the end because the high levels of bacterial life in the dark and deeply buried
lake are signs that it might support higher life-forms, such as microscopic animals like
tardigrades.
Meanwhile, the abundance of bacterial life in Lake Mercer mirrored the discovery of high
levels of bacterial life in Antarctica's nearby subglacial Lake Whillans in 2013 in an expedition
that Priscu also led.
Scientists theorize that the bacteria in Lake Whillans, and possibly Lake Mercer, are surviving
on deposits of carbon laid down by photosynthesizing organisms between 5000 and 10,000 years ago,
when the buried lakes may have been connected to the open ocean.
During their stay on the ice from mid-December last year, the expedition team used drills
and hot water to open a borehole from their camp at the frozen surface down to the buried
lake of liquid water.
The drill team bored through about 3,504 feet or 1,068 meters of ice, and the water below
was a chilly 30.8 degrees Fahrenheit or minus 0.65 degrees Celsius so that scientific researchers
could take water samples and sediment cores from the lake, which was about 49 feet or
15 meters deep at that spot.
The team had also lowered a specialized remotely operated underwater vehicle or ROV into the
dark waters of the buried lake, as well as several cameras, which they used to take images
and make a video of the lake floor.
The discovery has implications for the search for life on other planets, particularly on
planet Mars, where signs of a buried lake of liquid saltwater were seen in data reported
in 2018 by the European Space Agency's orbiting Mars Express spacecraft.
In fact, Priscu thinks that any life below the frozen surface of the planet Mars might
follow the patterns seen in Antarctica's subglacial lakes!
Let's hear what you think of NASA finding evidence of life on Mars in the comment section
below!