There are few frontiers in the world that can still be said to be unexplored. One of these terra incognita is the land beneath Antarctica’s ice sheets. Buried under kilometres of ice is a fascinating realm of canyons, waterways and lakes, which is only now being mapped in detail.
There are more than 400 known lakes in this harsh environment, and more are being discovered as technology advances. This water beneath the ice lubricates the interface between the ice sheet and its rocky bed, and thus controls the flow and behaviour of the ice itself.
Under such a large volume of ice, how is it possible for water to exist at all without freezing? The answer is pressure: when a large weight of ice is pushed onto water, it can stay liquid at temperatures well below the normal freezing point. What’s more, the large body of ice actually insulates the bed and protects it from the very cold air temperatures above.
The liquid water is created by heat from the Earth’s interior and from the friction generated as ice flows over the bedrock, which can melt the underside of the ice sheet. It is this water that flows into the subglacial lake basins and eventually into the ocean.
A tour around this subglacial landscape would take you first to the largest lake under the ice: Lake Vostok. At 12,500 square kilometres and with an average depth of 430 metres, Lake Vostok is the world’s sixth-largest lake by volume, but as it lies beneath some 3.5km of ice, it’s not easy to visit.
Using ice-penetrating radar and seismic techniques, scientists have mapped Lake Vostok to understand its origins. They have found that it may be up to 15 million years old. The lake has circulation patterns driven by freezing and thawing of the overlying ice, and even has small lunar tides.
Lake Vostok was discovered decades ago, but what is thought to be the second-largest lake under the ice sheet was first observed only this year. It is in Princess Elizabeth Land, East Antarctica, known as the “last pole of ignorance” because until recently it was virtually unmapped.
This region is also home to a huge canyon system, which extends all the way from the ice sheet interior to the coast. The system is as deep as the Grand Canyon but 100km longer.
Dynamic environments
So far our tour has focused on the central regions of Antarctica, where ice and water are relatively stable. In contrast, at the ice sheet’s dynamic edges near the coast we find fast-flowing regions called ice streams. Many of these have subglacial lakes in their catchments.
Tens to hundreds of kilometres in length, these lakes are short-lived, growing and draining over a period of just a few years. Evidence of this drainage process comes from satellite measurements of the height of the ice sheet. The surface can be seen to rise and fall, as the lake swells and then ebbs away again.
So far, at least 130 of these “active” lakes have been discovered. More are being found every year.
One example is Lake Whillans, in West Antarctica. Covering about 60 square km, it’s small in comparison with the gigantic Lake Vostok, but is by no means insignificant. In January 2013, a US research expedition drilled into the lake, extracting clean samples that were later found to contain microbial life.
Such life thrives in this harsh environment without sunlight for photosynthesis. Instead, the microbes depend on the oxidation of methane and ammonia, derived from sediments that are hundreds of thousands of years old. This momentous discovery of life in such a harsh and unforgiving environment may provide scientists with critical information on the development of marine life cycles.
Loose underpinnings
The water beneath the ice creates a mysterious and fascinating subglacial world, but it is also important because it lubricates the bed of the ice sheet and controls how fast the ice can flow. Where there is sediment under the ice, liquid water can make the ground unstable, while in other areas high pressure allows the ice to float on a pillow of liquid water. In both cases this reduces the friction at the base, allowing the ice to flow faster.
As scientists, we want to predict how the ice sheet will react to a warming climate. To do that, it is essential to pin down the role of water in the current flow rates of Antarctic ice. These fascinating lake and canyon features are therefore not only intriguing, but also play a crucial part in the future of the icy continent.
One of these terra incognita is the land beneath Antarctica's ice sheets. Buried under kilometres of ice is a fascinating realm of canyons, waterways and lakes, which is only now being mapped in detail. There are more than 400 known lakes in this harsh environment, and more are being discovered as technology advances.
Beneath East Antarctica's undulating ice sheet lies an ancient, river-carved landscape that provides a perfect snapshot of the region before glaciers covered the continent, a new study finds.
Researchers said on Tuesday they have detected buried under the continent's ice sheet a vast ancient landscape, replete with valleys and ridges, apparently shaped by rivers before being engulfed by glaciation long ago.
"Past studies have found some small mobile scavengers and predators, such as fish, worms, jellyfish or krill, in these habitats. Our study found the first ever record of a hard substrate—a boulder—community deep beneath an ice shelf, made up of probable filter-feeding animals such as sponges."
This remote body, named Lake Vostok, is by far the largest subglacial lake in the world. It persists despite surface temperatures that regularly hover around –60 degrees Celsius, because the bottom of the ice at this locale absorbs enough heat from the interior of the earth to keep the lake from freezing.
Antarctica has both saline and freshwater lakes. Antarctica is divided into West Antarctica and East Antarctica by the Transantarctic Mountains, which stretch from Victoria Land to the Ross Sea. The vast majority of Antarctica is covered by the Antarctic ice sheet, which averages 1.9 km (1.2 mi) in thickness.
Researchers have discovered an ancient river system hidden beneath the East Antarctic Ice Sheet. The landscape likely formed during the Cretaceous period, when dinosaurs roamed the Earth. Understanding the landscape beneath the ice can help predict how Antarctica will respond to climate change.
Hidden on the frozen continent are clues to its greener past. While Sir Ernest Shackleton is often heralded as the hero of polar exploration, he had many contemporaries, among them British naval captain Robert Falcon Scott, who along with four of his men is still buried under the snows of the Antarctic.
A momentous discovery has emerged from the depths of the Antarctic Ocean—an immense creature with 20 arms, displaying a remarkable similarity to a strawberry. Termed "Promachocrinus gregarious," this captivating organism has seized the attention of scientists and earned the informal name, "strawberry feather star."
Winter ice on the surface of Antarctica's Weddell Sea sometimes has an enormous hole called a polynya. A polynya that appeared in 2016 and 2017 offered a unique opportunity for oceanographers to monitor this expanse of ice-free water.
LOS ANGELES, March 5, 2024 /PRNewswire/ -- Viking® (www.viking.com) today announced its expedition team supported the discovery of a new colony of chinstrap penguins not previously known to science on Diaz Rock, near Astrolabe Island, in Antarctica.
You can think of these as mini- habitats for microbial life in what would otherwise appear to be an inhospitable environment. It is incredible how much life exists in and around ice and at such cold temperatures.
The “underside” of sea ice in the Arctic and Antarctic is a unique habitat, where roughly 1,000 different species of algae, which are largely unaffected by cold or lack of light, flourish. Serving as food for small crustaceans, they represent the basis of food webs in the polar seas.
Don Juan Pond is a shallow, flat-bottom, hyper-saline pond. It has the second-highest total dissolved solids on record, 1.3 times greater salinity than the Dead Sea. Salinity varies over time from 200 to 474 g/L, dominated by calcium chloride. It is the only Antarctic hypersaline lake that almost never freezes.
Antarctica also has some relatively small regions that are clear of ice and snow, and there are some surface lakes in these regions. They called for on the ground seismic studies, or drilling, to determine a more reliable number. These lakes are buried beneath deep layers of glacial ice.
It's not habitable in the current ice age… SO, NO, it wouldn't be habitable in another ice age if it happens! Antarctica is under 2 kilometres of ice at present.. and apart from scientific research is not habitable or used for living purposes now…and has not been for something like 45 MILLION years!!
The Antarctic continent lies on a large landmass. Underneath that smooth ice sheet there are mountains and valleys. The surface of the Antarctic Ice Sheet is up to 4000 m high, and in places the ice is 4000 m deep, but the Gamburtsev Mountain range is up to 2,700 m high and lies underneath the East Antarctic Ice Sheet.
Unlike Antarctica, there's no land at the North Pole. Instead it's all ice that's floating on top of the Arctic Ocean. Over the past four decades, scientists have seen a steep decline in both the amount and thickness of Arctic sea ice during the summer and winter months.
Although many different types of Antarctic soils exist, in general, they comprise a surface pavement (i.e., a layer of gravel, stones or boulders formed largely by weathering and the removal of fine materials mainly by wind action) and a seasonally thawed active layer over permafrost.
Tiny critters known as plankton feed all kinds of fish, which feed large marine mammals like seals. All this activity produces detritus—and dead animals—that one day become marine snow. But the Antarctic critters on this particular rock don't live under a bustling water column. They live under a half-mile of solid ice.
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