From barren mountains to sweltering deserts, freezing polar regions to deep-sea hydrothermal vents; there’s no shortage of extreme environments on Earth. Although life’s tough in these harsh habitats, organisms always seem to find a way, cropping up in even the most surprising environments. And the Antarctic is continually proving to be a wonderful example of this, as scientists have just discovered a variety of marine animals seemingly thriving under almost half a mile of ice in a cold, dark and desolate world.
The discovery was made as part of the Whillans Ice Stream Subglacial Access Research Drilling (WISSARD) project, which aimed to examine the Antarctic’s “grounding zone,” where ice, sea and land all meet. The idea behind the expedition was to collect sediment from this hard-to-reach area, which they hoped would shed light on the mechanics of ice sheets and how they might contribute to sea-level rise.
To become the first group to both reach and sample this region, scientists enlisted the help of a hot-water drill to punch through almost 740 meters (2,500 feet) of the Texas-sized Ross Ice Shelf, which is the world’s largest body of floating ice. They then dropped a specially designed, equipment-laden vehicle through the hole and sent it exploring around the area.
The underwater robot’s camera revealed the seafloor as barren and rocky, and the sediment and water samples taken weren’t exactly teeming with microbial life. Initially, no signs of larger marine life were spotted, which wasn’t surprising given the fact that the water is a mere -2oC (28oF) and perpetually dark. Furthermore, life is restricted to a 10 meter (33 ft) deep stretch between the ice and seafloor. Then, much to their surprise, the scientists spotted something moving. As described in Scientific American:
“A graceful, undulating shadow glided across its view, tapered front to back like an exclamation point—the shadow cast by a bulb-eyed fish. Then people saw the creature casting that shadow: bluish-brownish-pinkish, as long as a butter knife, its internal organs showing through its translucent body.”
That was one of a bunch of fish the researchers would observe that day, alongside numerous other life forms including crustaceans and jellyfish. The find was certainly exciting, although perhaps not completely unexpected given the fact that life has been found under the Ross Ice Shelf before. However, this sampling site marks the closest area to the South Pole where marine life like this has been observed.
“It is fascinating to see so much marine vertebrate and invertebrate life so far away from the open ocean,” chief scientist Slawek Tulaczyk said in a news release. “I have spent my scientific career studying how this ice sheet may contribute to future global sea level rise. However, I now realize that retreat of the ice sheet may also impact a unique ecosystem.”
Alongside being cold and dark, the area is severely lacking in food, which begs the question: what are these organisms eating to survive? There are no plankton, but there are carbon-rich marine sediments. The researchers are therefore keen to find out more about how these animals survive in this unforgiving environment.
[Via National Science Foundation, Live Science, PopSci, Scientific American and Smithsonian]
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