The water in the subglacial lakes is at about freezing but is just warm enough to flow around in a liquid state. This is because the immense pressure of the ice – which is often over a mile thick – is so intense that it warms the water on the very bottom.
Additionally, the warmth of magma that flows underneath the earth’s crust comes from below the lakes and causes the water to warm, just enough to be in a liquid state. So they aren’t exactly hot springs, but they exist in a sub-frozen state that only enables them to flow around and be considered freshwater lakes.
The Southern Ocean surrounds much of Antarctica and contains many kinds of polar wildlife, including whales, seals, and micro-organisms. The Southern Ocean is full of icebergs that have broken off of Antarctic glaciers and ice sheets, so it can be complicated for a ship to navigate.
The water in the subglacial lakes of Antarctica flows in such a way that it pools together and streams down, underneath the glaciers, into the Southern Ocean. This freshwater that flows into a salty ocean has some impact on coastal wildlife, and the effects are something that researchers are trying to understand.
The Subglacial Lakes Have An Otherworldly Appearance
The lakes that exist underneath Antarctica’s glaciers bear no resemblance to anything that we are aware of on this earth. Researchers who study them have likened their appearance to extraterrestrial landscapes because the structures and formations in them are so unique. In fact, studying them may provide insight into astrobiology, the field that studies the possibility of life on other planets.
The lakes are lined with ice that is full of bubbles, giving them an ethereal appearance that seems like it is out of this world. They are also very dark and very, very cold.
The lakes lie underneath glaciers that can be a mile thick or more. While ice may have a clear appearance in minimal amounts, this dense layer of ice has an opaque appearance that is solid white all the way through. You cannot see through a glacier.
As a result, no sunlight can reach the subglacial lakes. They are pitch black, so photosynthesis – the process whereby plant and some microbial life forms synthesize energy from sunlight – is unable to happen there. By all accounts, there should not be any life that exists down there.
There are abundant signs of life in the subglacial lakes, but none of the macro-organisms that we are familiar with. There are no penguins, fish, whales, or even plants such as seagrass or kelp. All of life is microbial, and it seems to be thriving.
Microbial life is incredibly resilient and can thrive in some of the harshest, most unforgiving climates on the planet. Evidence of the microbial life in Antarctica’s subglacial lakes is seen in the chemical composition, which includes the chemical byproducts of life processes that including eating, eliminating waste, and dying.
The fossil water inside the subglacial lakes has high levels of dissolved minerals, which support the microbial lifeforms that live there. The minerals include carbon and other nutrients, which affect the chemical composition of the coastal areas of the Southern Ocean.
The lakes periodically drain out into the Southern Ocean and then are filled again by the water that flows and collects together. As the water flows out into the ocean, the minerals flow out and join the salty Southern Ocean. As more water flows in, the minerals recollect. The carbon levels can replenish themselves within 4.8 to 11.9 years.
Scientists have concluded that the movement of magma underneath the earth’s crust causes the tectonic plates on the surface to move. They slide around on the ocean of magma, so slowly that the movements are imperceptible but measurable over the long term.
A very similar scenario exists between the subglacial lakes and surface ice sheets. As the water flows around and drains into the Southern Ocean, the ice moves around. This movement causes the lake water to flow even more rapidly; this relationship between the lakes and the glaciers can actually be seen by measuring surface ice.
While finding one of these subglacial lakes would certainly be extraordinary, as of 2018, researchers had identified 379 of them! What this means is that they may be much more ordinary than scientists had initially thought, and estimates say that we are sure to discover many, many more.
Scientists have been finding the lakes by using radiography; they discovered the first one in 1970. The largest known subglacial lake is Lake Vostok; it is hundreds of meters deep, 50 kilometers across, and 240 kilometers long! Some areas have higher concentrations of lakes because of their unique geography, which is more conducive to lake formation.
They May Have Been In Existence For 35 Million Years Or More
The subglacial lakes of Antarctica have some of the most extreme conditions on the entire planet. The immense pressure upon the water affects the temperature at which water freezes, making them more akin to alien liquid bodies than other water bodies on earth.
These lakes are incredibly old; some estimates say that they may be 35 million years old or more! They have been a longstanding feature of Antarctica’s landscape and have been affecting the ice sheets in ways that scientists are only now beginning to understand.
Scientists In Antarctica Also Study The Continent’s Wildlife
There are very few land animals that live in Antarctica. The largest animal that lives solely on the land there is a flightless bird known as Belgica Antarctica, and it is only one-quarter of an inch in size! Most of its wildlife, including its penguins, is considered to be marine.
The wildlife of Antarctica includes killer whales, blue whales, and other large marine mammals that thrive in icy water, as well as seals and colossal squids. Many different types of penguins live there, including emperor penguins, southern rockhopper penguins, king penguins, Gentoo penguins, and chinstrap penguins.
While the wildlife in Antarctica is spectacular, large animals only occupy a tiny portion of the continent – mostly along its coastline. Its smaller lifeforms include phytoplankton, mites, nematodes, lice, tardigrades, springtails, krill, and rotifers.
However, most of the life that lives on Antarctica is microbial. Algae are abundant, including microscopic diatoms. Some bacteria, in particular, favor the frigid conditions, as they have been found living as deep as 2600 feet underneath the ice. Microbial life is incredibly resilient and can thrive in some of the harshest conditions on the planet, where scientists least expect to find any living thing.
Geologic evidence suggests that tundra vegetation, including some forests, covered parts of Antarctica until as recently as about 15 million years ago. However, its inhospitable climate has made plant life there extremely rare. Plants in Antarctica consist mostly of mosses and liverworts, which are primitive plants that do not have a vascular system,
Some flowering plants live in a few places along Antarctica’s coastline, and they only grow for a few weeks out of the summer. Researchers who study plant life in Antarctica can learn about some of the conditions on earth in its distant past.
Researchers have identified approximately 1150 different types of fungi in Antarctica. Many of these fungi are very primitive, with very simple morphology, low metabolisms, and undifferentiated structures. These primitive features make them ideally suited to life in the frozen Antarctic tundra.
Fungi in Antarctica are so abundant that they have had a noticeable impact on some of the rock formations there. Scientists who study the fungi estimate that they may have qualities and features similar to extraterrestrial life on places such as Mars. Studying these unique forms of life helps provide a window into both early conditions of life on earth and what life may be like if it exists elsewhere in the universe.
Sources: “50 Amazing Facts About Antarctica,” by Andrea Thompson. Live Science. March 10, 2014. “Scientists Reveal What Living and Working in Antarctica Is Really Like,” by Jesslyn Shields. How Stuff Works. February 2, 2017. “Almost alien: Antarctic subglacial lakes are cold, dark and full of secrets.” Science Daily. March 4, 2020. “Antarctica.” Wikipedia.