There could be something big living deep beneath the Antarctic ice

Antarctica is one of the most extreme environments on Earth. It is also one of the most unexplored.

Many of us think of the continent as a vast, white wasteland, populated by nothing more than penguins and seals. But beneath its icy surface, scientists are beginning to discover vast networks of complex life forms that have not been seen anywhere else on the planet.

There are two different types of Antarctic ice: land ice and sea ice. Sea ice is formed when the upper layers of the Southern Ocean freeze over. The ice cover is seasonal and, in the summer, most of this ocean ice melts away.

Blooms of photosynthetic algae have been observed in these regions as soon as the ice melts. But until recently, it was often assumed that the packed sea ice prevented any light from reaching the layers beneath before this seasonal transition.

This stock image shows a frozen Antarctic landscape. Beneath the barren ice are ecosystems teeming with life.
NicoElNino/Getty

However, new research suggests that blooms of photosynthetic algae, called phytoplankton, can grow, and even thrive, before the ice retreats.

Phytoplankton forms the basis of most aquatic food webs and supports the growth of other complex life forms. Using data collected from NASA’s Earth surveillance satellites and on-site ocean floats, researchers from Brown University and the University of Auckland have found evidence for vast swathes of these photosynthetic life forms living beneath the frozen surface.

“Finding these blooms helps challenge the paradigm that regions under sea ice are devoid of life, and introduces important new questions about the food webs that might lie under the ice in Antarctica,” Christopher Horvat, who led the study, published in the journal Frontiers in Marine Sciencetold Newsweek.

“We think they could cover up to 5 million square kilometers of the under-ice region in the Southern Ocean.”

The sea ice in the Southern Ocean is composed of discrete sheets of packed ice. In between these sheets, small areas of open water allow light to pass through, permitting photosynthesis.

sea ​​ice floe
This stock image shows sea ice floes. Gaps between sheets of sea ice allow light to penetrate into the water beneath.
pum_eva/Getty

Huw Griffiths, a marine biogeographer with the British Antarctic Survey, explained that the sea ice itself is usually only about three to ten feet thick and therefore does also allow some light through directly to reach the surface waters below.

However, life has also been discovered in areas that have never seen the light of day. “Most ice shelves are so thick that no light reaches the sea floor below,” Griffiths told Newsweek.

Ice shelves are made mostly of the second type of Antarctic ice: land ice. They are formed when huge slabs of ice are pushed off the land onto the ocean surface. Unlike sea ice, these slabs can be thousands of feet deep.

In 2021, Griffiths and his team discovered marine life forms on a boulder on the seafloor under an Antarctic ice shelf, 3,000 feet beneath the surface.

“We know very little about life under Antarctica’s floating ice shelves. Ice shelves cover around a third of the continental shelf—1.5 million square kilometers—but our knowledge is based on a handful of records from boreholes drilled through the ice shelves,” he said .

“These holes give us small snapshots of what lives on the seafloor and the water column, but the majority of what we know comes from short video clips and photographs covering a very small area.

“Current theories on what life could survive under ice shelves suggest that all life becomes less abundant as you move further away from open water and sunlight,” he continued.

“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.”

Moving inland, Antarctica’s frozen wasteland conceals a hidden kingdom of hundreds of subglacial lakes and rivers, teaming with life. In 2014, Lake Whillans, the third largest lake on the continent, which lies 2600 feet beneath the West Antarctic Ice Sheet, was shown to contain nearly 4,000 different microbial species.

In June, researchers from New Zealand recorded swarms of shrimp-like creatures in an underground river beneath the Ross Ice Shelf on the continent’s southern edge.

Taken together, these discoveries indicate just how diverse the different life forms are under the Antarctic ice.

“Animals surviving deep under ice shelves need to be adapted to extreme cold, with water temperatures as low as -2.2 degrees Celsius (28 degrees Fahrenheit),” Griffiths said. “They would also need to be adapted to low amounts of food, in a similar way to deep sea creatures. These organisms live hundreds of kilometers from the nearest daylight and sources of fresh phytoplankton.”

Such adaptations open up the possibility that similar ecosystems could exist in other frozen landscapes.

“The discovery of complex animal life—more than [just] microbes—in such extreme conditions suggests that complex life might possibly survive beyond the Earth on frozen moons, such as Jupiter’s Europa, Ganymede and Callisto, and planets, where liquid water flows beneath the icy surface,” Griffiths said.

Jupiter's moons
This stock image shows Jupiter and its moons. The discovery of lifeforms under the Antarctic ice suggests that other complex organisms could survive in similarly extreme extraterrestrial environments, like Jupiter’s frozen moons.
Dottedhippo/Getty

But these studies also tell us about life on our own planet.

“Antarctica is one of the most extreme environments on Earth,” Griffiths said. “We have names for close to ten thousand species but every time we visit, we find that between 10 and 20 percent of the species we find are new to science. There could be as many as ten thousand more species waiting to be discovered!

“Working in Antarctica is never boring, always challenging and always surprising. It also requires a huge amount of international cooperation–no one country could study this huge here continent alone,” he said.

As human influence stretches to every corner of the planet, Antarctica’s untouched ecosystems are coming under threat. As a result of global warming, the Antarctic ice sheets are melting at a rate of approximately 150 billion tons per year, with devastating consequences on sea levels worldwide.

“Antarctica faces many challenges in its future, with climate change and human impacts already altering the habitats we find down there,” Griffiths said. “The ice shelves and sea ice are already changing, and the seawater is becoming warmer and more acidic. We have found microplastics in the water, sediments and animals, and other pollutants from industrial nations have found their way down into the Southern Ocean.

“Most people don’t know much more about Antarctica’s unique wildlife and biodiversity than the penguins and seals that live at the surface. But over 90 percent of Antarctic species are found on the seafloor and over half of those are found nowhere else on Earth.

“This makes Antarctica a special and globally important biodiversity hotspot and somewhere that needs our help to stay healthy and able to support such an abundance of life.”

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about Antarctica? Let us know via [email protected]


References

Horvat C, et al., Evidence For Phytoplankton Blooms Under Antarctic Sea Ice, Front. Mar. Sci., November 17 2022, doi: 10.3389/fmars.2022.942799

Griffiths HJ, et al., Breaking All the Rules: The First Recorded Hard Substrate Sessile Benthic Community Far Beneath an Antarctic Ice Shelf, Front. Mar. Sci. February 15 2021, https://doi.org/10.3389/fmars.2021.642040

Christner, B., Priscu, J., Achberger, A. et al., A microbial ecosystem beneath the West Antarctic ice sheet, Nature, August 20 2014, https://doi.org/10.1038/nature13667

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