Unprecedented Subglacial Lakes Discovered in Canadian Arctic

Environments with the power to unlock the secrets of other worlds have been found several hundred meters beneath the ice of the Canadian Arctic. A joint study published last month in Science Advances predicted the presence of two hypersaline subglacial lakes on either side of the east-west ice divide of the Devon Ice Cap, an ice cap located in Nunavut, Canada, known for its rugged terrain of both mountain ridges and bedrock troughs. These are not only the first subglacial lakes to be found in the Canadian Arctic but also the first hypersaline subglacial lakes reported to date, each estimated to be around 5 and 8.3 square kilometers.

A map of the Devon Ice Cap and subglacial lake locations (Source: Science Advances).

The lakes, which are described as “unprecedented” in the study, are of great interest to researchers for their unique characteristics: both are hypersaline and spatially isolated. This isolation from outside influences may reach back 120,000 years ago, when the lakes were covered by glacial ice.

The lakes could represent significant microbial habitats, which could be used as analogs to study the conditions for potential life on other planets. Specifically, the study states that these lakes could represent similar environments to the potential brine bodies within Europa’s ice shell or Martian polar ice caps.

“Because these subglacial systems are isolated for tens of thousands of years, they are excellent candidates to explore life processes in extreme conditions,” states Alexandre Anesio, a professor and researcher at the University of Bristol who studies the biogeochemistry of the cryosphere. He sees this opportunity as “one of the best ways to explore the limits of life on other planets.”

The newfound potential of these lakes came as a shock, Anja Rutishauser, one of the study’s researchers, told GlacierHub. “The original research goal was to better understand these basal conditions of Devon Ice Cap, as they largely affect ice dynamics and how ice flow might change under future climatic conditions. We expected to find subglacial water signatures in the faster-flowing marine-terminating outlet glaciers, but certainly not in the center of Devon Ice Cap.”Rutishauser added that the ice cap was expected to have ice frozen to the ground, not liquid water or entire subglacial lakes.

A UTIG research scientist operating radar instruments inside a DC-3 aircraft during a survey flight over Devon Ice Cap (Source: Anja Rutishauser).

The discovery was made when the researchers analyzed radio-echo sounding measurement data. Models further analyzed the basal ice temperature. It measured 10.5 degrees Celsius, which led to the conclusion that the hypersalinity was significantly depressing the freezing point temperature. Further, the study found that this is in “agreement with surrounding geology, situated within an evaporite-rich sediment unit containing a bedded salt sequence,” the likely source for the salt. The exact origins of the subglacial lakes and the processes that formed them remain unclear, but similar bodies can offer clues to the specifics of the Canadian lakes.

According to the study, Taylor Glacier in Antarctica contains the most comparable subglacial fluid to the Canadian lakes, with similar temperature and salinity measurements. However, it is sourced from ancient marine water and not spatially isolated. Taylor Glacier’s outflows have been found to have active microbial communities, which leads researchers to believe the same is possible in the Devon Ice Cap.

Taken from the DC-3 aircraft during transit and aerogeophysical survey flights over Canadian Arctic ice caps and glacier (Source: Anja Rutishauser).

Many subglacial lakes in Antarctica and Greenland share other similarities with the Canadian lakes, further bolstering the study’s evidence. “Almost all the effort on subglacial lake exploration is concentrated in Antarctica, but this study reveals that there are other excellent locations for subglacial lake exploration,” according to Anesio. However, he believes further exploration is no trivial task considering the engineering challenge to drill cleanly into a subglacial lake without the risk of contaminating it. “However, it is certainly worth a try,” he said.

This is precisely how the researchers plan to follow up on their unprecedented discovery. “Our long-term vision is to cleanly access these lakes in order to derive if life exists,” added Rutishauser.

For now, Rutishauser said the research team is partnering with the W. Garfield Weston Foundation this spring to perform a more detailed aerogeophysical survey over Devon Ice Cap to derive more information about the lakes, including their hydrological and geological contexts.

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Roundup: GLOFs, Presidential Warnings, and Glacial Lakes

Obama: Climate Change ‘Could Mean No More Glaciers In Glacier National Park,’ Statue of Liberty

From Breitbart: 

“During Saturday’s Weekly Address, President Obama stated, “the threat of climate change means that protecting our public lands and waters is more important than ever. Rising temperatures could mean no more glaciers in Glacier National Park. No more Joshua Trees in Joshua Tree National Park. Rising seas could destroy vital ecosystems in the Everglades, even threaten Ellis Island and the Statue of Liberty.”

To read the full transcript of the President’s Weekly Address, click here.

 

Melting Glaciers Pose Threat Beyond Water Scarcity: Floods

From VOA News: 

A melting block of ice from a Pastoruri glacier in Huaraz, Peru.
A melting block of ice from a Pastoruri glacier in Huaraz, Peru. Source: Associated Press.

The tropical glaciers of South America are dying from soot and rising temperatures, threatening water supplies to communities that have depended on them for centuries. But experts say that the slow process measured in inches of glacial retreat per year also can lead to a sudden, dramatic tragedy. The melting of glaciers like Peru’s Pastoruri has put cities like Huaraz, located downslope from the glacier about 35 miles (55 kilometers) away, at risk from what scientists call a ‘GLOF’ — Glacial Lake Outburst Flood.”

Click here to read more about the risk of glacial lake outburst floods from GlacierHub’s founder and editor, Ben Orlove.

 

Yukon has a new lake, thanks to a retreating glacier

From CBC News: 

Cultus Bay
Cultus Bay, now cut off from Kluane Lake by a gravel bar. Source: Murray Lundberg.

“Yukon has lost a river, and now gained a lake, thanks to the retreating Kaskawulsh glacier.

Geologists and hikers first noticed earlier this summer that the Slims River, which for centuries had delivered melt water from the glacier to Kluane Lake, had disappeared — the glacial run-off was now being sent in a different direction. Now, the level of Kluane Lake has dropped enough to turn the remote Cultus Bay, on the east side of the lake, into Cultus Lake. A narrow channel of water that once connected the bay to the larger lake is gone, exposing a wide gravel bar between the two.”

To read more, click here.

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Glacier Past Unveiled Through Sediments

Svalbard: Ny Ålesund. Note: this lake was not part of the study. Courtesy of James Stringer/Flickr
Svalbard: Ny Ålesund. Note: this lake was not part of the study. Courtesy of James Stringer/Flickr

Researchers have long used preserved sediment layers in glaciers as time records to understand the climate of the past. But now, researchers, publishing in Quaternary Science Reviews, have used lake sediments in glacier-fed Lake Hajeren in Svalbard to recreate glacier variability during the Holocene period.

The sediments, which were deposited over millennia, have been undisturbed, allowing researchers to develop a continuous and full record of glaciers as early as 11,700 calibrated Before Present (BP). The dates were calculated using radiocarbon calibration, meaning that the dates have been compared to other radiocarbon samples. Atmospheric carbon varies over time, so it does not necessarily correspond to the current Gregorian calendar. By comparing different radiocarbon samples, researchers hope to develop a more accurate dating system.

The researchers’ complete record revealed a number of new findings about the advance and presence of the Svalbard glacier. Sediments in Lake Hajeren indicated that between 3380 and 3230 cal BP there was a glacier advance that lasted more than 100 years. The glacier advance had never before been recorded.

Researchers also noted that during the deglaciation period before 11,300 cal BP, glaciers in Svalbard remained, and that between 7.4 and 6.7 thousand cal BP, glaciers disappeared. It wasn’t until 4250 cal BP that glacier reformation began. The variability in glacier presence and formation can be attributed to pulses from the melting Laurentide Ice Sheet, episodes of cooling in the Atlantic and reduced isolation during summers.

“These findings highlight the climate-sensitivity of the small glaciers studied, which rapidly responded to climate shifts,” the authors wrote.

Their research contributes to a body of work looking to better understand the driving forces behind climate variability in the Arctic, the region most affected by climate change. The Arctic also has a disproportional impact on the global climate compared to other parts of the world.

Arctic response to climate change can also be used to develop climate models that estimate the impacts of global warming.

“The rapid response of the small Hajeren glaciers improves our understanding of climate variability on Svalbard, suggesting that the Holocene was punctuated by major centennial-scale perturbations,” the authors concluded. “As such, this study underlines the value of glacier-fed lake sediments in contextualizing Arctic climate dynamics.”

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