Washington: In a ground-breaking discovery, glacial geologists in Antarctica have discovered fish and other aquatic animals living in perpetual darkness and cold - beneath a 740 metre-thick roof of ice.
The animals inhabit a wedge of seawater only 10 metres deep, sealed between the ice above and a barren, rocky seafloor below.
The location is so remote and hostile that scientists expected to find nothing but scant microbial life, the scientific journal Nature reported.
"I am surprised. The discovery provides insight into what kind of complex but undiscovered life might inhabit the vast areas beneath Antarctica's ice shelves comprising more than a million square kms of unexplored seafloor," said Ross Powell, glacial geologist from Northern Illinois University, who co-led the expedition with two other scientists.
The team of ice drillers and scientists made the discovery after lowering a small, custom-built robot down a narrow hole they bored through the Ross Ice Shelf - a slab of glacial ice the size of France that hangs off the coastline of Antarctica and floats on the ocean.
The remote water they tapped sits beneath the back corner of the floating shelf, where the shelf meets what would be the shore of Antarctica if all that ice were removed.
The spot sits 850 km from the outer edge of the ice shelf, the nearest place where the ocean is in contact with sunlight that allows tiny plankton to grow and sustain a food chain.
The expedition was funded by the US National Science Foundation.
The robot, called Deep-SCINI, stayed down in the wedge of seawater and captured translucent fish that came closer, swimming from one motionless perch to another over a period of 20 minutes until they came to within half an arm's length of the camera.
These fish, attracted perhaps by the novelty of light, were "curious and docile".
The robot encountered 20 or 30 fish.
"It was clear they were a community living there, not just a chance encounter," Powell added.
The translucent fish were the largest but Deep-SCINI also encountered two other types of smaller fish - one blackish, another orange - plus dozens of red, shrimpy crustaceans.
"We have to ask what they are eating. Food is in short supply and any energy gained is hard won. This is a tough place to live," Powell said.