Researchers have discovered a never-before-seen ecosystem lurking in an underground river one third of a mile beneath an Antarctic ice shelf. The team of scientists from New Zealand drilled through the ice shelf and dropped a camera into the cavern below. Hundreds of amphipods—small, shrimp-like crustaceans—swarmed the camera as it descended into the river, reports Live Science's Harry Barker.
The subterranean habitat was found beneath the outer edges of the Ross Ice Shelf, the world's largest body of floating ice, on the southern edge of Antarctica, during a research project focused on documenting and piecing together how climate change is melting the ice shelf and affecting associated ecosystems, a statement explains.
Previous satellite images showed a groove in the ice shelf close to where it met with the land, and the team suspected it was an under-ice estuary. Researchers have long speculated about a network of flowing freshwater lakes and rivers beneath the Antarctic ice sheets but had yet to explore them, reports Eva Corlett for the Guardian. After the researchers identified it as a subterranean river and gathered at the site in Antarctica, they drilled down 1,640 feet below the ice’s surface, using a specialized hot water drill system developed at Victoria University of Wellington to melt the ice. Soon after they reached the hidden cavern, the team sent the camera down. Initially, all they saw was blurry flecks that looked like detritus floating around. A quick camera-focusing showed that it was actually living crustaceans, reports Live Science.
“In a normal experiment, seeing one of these things would have you leaping up and down for joy. We were inundated. Having all those animals swimming around our camera means there’s an important ecosystem process happening there, which we will do more research on by analyzing water samples to test for things like nutrients,” says National Institute of Water and Atmospheric Research marine physicist Craig Stevens in the statement. Aside from the discovery of the amphipods, the team found that the water column split into four to five distinct layers of water flowing in different directions, Live Science reports. Water is often found in distinct layers that do not easily mix, due to differences in temperature and salt content.
As Antarctic ice shelves float, water constantly circulates underneath them, coming in and out of the open ocean. Some of the water columns are warm and can cause ice shelves to melt, per the statement. While the research team was observing the underwater river, the Hunga Tonga-Hunga Ha'apai volcano in the South Pacific erupted from late December 2021 to mid-January 2022 causing a tsunami; the scientists picked up on pressure changes in the underground cavity from this event.
“Seeing the effect of the Tongan volcano, which erupted thousands of kilometers away, was quite remarkable,” Stevens said in the statement. “It is also a reminder about just how connected our whole planet is.”