Isolated lakes found beneath Canadian ice sheet

The sun over a windswept ice fieldImage copyright ANJA RUTISHAUSER
Image caption The lakes lie beneath the Devon ice cap in the Canadian Arctic

Researchers have found lakes that may shed new light on icy worlds in our Solar System. High in the Canadian Arctic, two subglacial bodies of water have been spotted beneath over 500 metres of ice. The water has an estimated maximum temperature of -10.5C, and would need to be very salty to avoid freezing.

There are thought to be similar cold, saline conditions in the subsurface ocean of Jupiter’s moon Europa, yet also the potential to host life.

The findings, from a team led by the University of Alberta, have been published in Science Advances.

Satellite map of the Devon ice cap, showing the location of Devon island in the Canadian Arctic and two long lakes in the middle of the ice sheetImage copyright NASA/ANJA RUTISHAUSER
Image caption At 1,200m – 1,700m above sea level, the lakes sit in long basins in a mountain range

A Canadian first

The two lakes appeared in a radar survey of the Devon Ice Cap, which sits on Devon Island, in Canada’s northern Nunavut territory.

“I was super surprised, and a little bit puzzled,” Anja Rutishauser, the study’s lead author, said of the discovery. “I was definitely not looking for subglacial lakes.”

View from a plane window - the wing is visible to the right. A mountain range with a series of flat, snow-covered valleys in betweenImage copyright GREGORY NG

Although water systems beneath large ice sheets are being found to be increasingly common, Devon Island’s ice cap was thought to be frozen to the bedrock beneath.

These are the first subglacial lakes to be observed in the Canadian Arctic, and are estimated to cover areas of five and eight square kilometres respectively.

“It’s an amazing finding, and one that I really wasn’t expecting from the geophysical survey of this small ice cap,” commented Prof Martin Siegert from Imperial College London, who was not involved in the study.

“To my knowledge, this is a unique lake system. Of the [more than] 400 subglacial lakes in Antarctica, all of them are thought to comprise fresh water. Hence, whatever might be living in it may also be unique,” he added.

A red aeroplane stationary on a landing strip. Ice field and mountains visible in the background.Image copyright TOM RICHTER
Image caption Surveys were conducted using radar antennae, mounted to the wings of an aircraft

Life below zero

The water in the lakes is estimated to be five times as salty as seawater, allowing its freezing point to be lowered below that of fresh water.

Other subglacial lakes in Greenland and Antarctica contain fresh water, generated by melting at the base of the ice. Geothermal heat rises from the underlying rock, and is insulated by the thick ice sheet above.

The Canadian ice sheet is not thick enough to provide this insulation

Salt-rich water has been studied beneath Taylor Glacier in Antarctica’s McMurdo Dry Valleys, but this is supplied by an ancient marine water basin.

The mountainous location of these lakes places them above previous sea levels, and their salinity is derived from the high salt content of surrounding rock.

“It is interesting,” notes Prof Jemma Wadham from the University of Bristol, “that the more places we look, the more subglacial lakes we find. Just like in non-glacial environments, there could be a huge diversity of lake types and life habitat conditions, and one size does not fit all.”

A scientist with their back turned, operating radar equipment aboard an aircraftImage copyright ANJA RUTISHAUSER
Image caption Radar readings were taken across four years

A pocket of Europa

There are many answers researchers want to search for next. There may be an entire network of lakes in this region, beyond the two so far observed, and their size has yet to be determined.

However the potential for these environments to host life is a pressing question, as they may represent a largely isolated microbial habitat.

The study’s authors suggest the lakes may have been sealed off from surrounding environments for up to 120,000 years.

“The probability of life to exist in these systems is high, though the modelled temperatures might suggest that the biological activity would be severely limited due to the low temperature,” Dr Alison Murray of Nevada’s Desert Research Institute told BBC News.

From the cockpit of the plane: a chain of snowy mountains with an ice-filled valley in betweenImage copyright GREGORY NG
Image caption View from the cockpit of a research flight

They may also provide a window to life beyond Earth.

Dr Claire Cousins from the University of St Andrews explains: “While the chemistry of these lakes may be somewhat different to ocean environments on icy moons such as Europa, their otherwise extreme conditions will help us understand the habitability of hypersaline sub-ice environments.”

While further radar surveys are next on the list, Anja Rutishauser and her colleagues hope to be able to drill into the lakes’ waters one day, to better understand any ecosystem within.

Such work could, Dr Murray says, provide “a key to understanding the life-supporting nature of such systems which may occur in the icy and ocean worlds of the Solar System and beyond.”

Read more at www.bbc.co.uk

Trackback from your site.

Comments (2)

  • Avatar

    Joseph A Olson

    |

    Lake Vostok in Antarctica is under 2 miles of ice with a surface temperature to -89°C and is 4°C fresh water with thousands of DNA variations. Geothermal is underrated in magnitude and consistency.

    Reply

  • Avatar

    jerry krause

    |

    Hi Joe,

    It is not that “Geothermal is underrated in magnitude and consistency”, it is that what is being ignored is that the earth’s surface (including its ice surfaces) is ultimately only cooled by radiation (emission) sublimation and that the ice keeps the earth’s mineral surface from being warmed above 4C (because at this temperature liquid water is most dense) by melting. Then, the 2 mile layer of ice insulates its warmer base from its surface, which can never warm above 0C because at the surface the ice will melt at this temperature. So the minimum temperature difference between the ice surface and its base would have to be 4C unless the insulating property of ice allows its surface to be cooled by emission and sublimation far below 0C.

    Have a good day, Jerry

    Reply

Leave a comment

Save my name, email, and website in this browser for the next time I comment.
Share via