The Ross Ice Shelf, the largest on Earth, is far from having revealed all its secrets. There are still many questions that need to be answered and are a burning issue for researchers. And then suddenly there are answers to questions that may not have been asked yet. This is what happened to a New Zealand research team hoping to find and study a freshwater river beneath the Ross Ice Shelf. They located the river and bore down to it. What they discovered inside caused a big surprise among the team: masses of amphipods!
About two years earlier, Huw Horgan, associate professor at the Antarctic Research Centre at Victoria University of Wellington, New Zealand, discovered a groove in the ice on satellite images of the Ross Ice Shelf. Craig Stevens of the National Institute of Water and Atmospherics (NIWA) says in a report that the groove looked like an estuary under the ice.
There has long been a suggestion that beneath the ice shelf is a network of hidden freshwater rivers and lakes. However, there have been no direct studies of the rivers to date. Therefore, the research team traveled again to the Ross Ice Shelf to explore the hidden rivers.
However, it was more difficult than expected to find the groove on the ice. “It looked dramatic from the satellite imagery, but when you get there and you’re looking around you’re thinking: ‘Where’s the groove?’ But then we find this tiny, gentle slope and guessed we’d got the right spot,” says Stevens, describing the search.
Using a hot water hose, they melted their way 500 meters through the ice directly into a meltwater-filled, cathedral-like cavern under the ice that is up to 10 kilometers long, about 300 meters wide and 250 meters deep, the CNET platform reported.
There, they observed things that no one had ever seen before. “There was a huge element of discovery for us. The first surprise was that the meltwater tube wasn’t nice and smooth as we expected – it had a strange structure and was quite narrow, with loads of undulations. It looked like a loaf of bread, with a bulge at the top and narrow slope at the bottom. The water within comprised four or five different layers flowing in different directions,” Stevens said. “This changes our current understanding and models of these environments. We’re going to have our work cut out understanding what this means for melting processes.”
But the real surprise was waiting in the river. When the researchers tried to inspect the water more closely with a camera, amphipods were buzzing around in front of the lens. “For a while, we thought something was wrong with the camera, but when the focus improved, we noticed a swarm of arthropods around 5mm in size,” Stevens tells The Guardian. “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 clearly an important ecosystem process happening there, which we will do more research on by analysing water samples to test for things like nutrients.”
However, this was not the only spectacular discovery the researchers made. During the time they were on site, there was a massive eruption of the Tonga volcano Hunga Tonga-Hunga Ha’apai. The instruments the researchers used to study the hidden river detected a significant change in pressure as the tsunami caused by the eruption made its way through the cavities in the ice.
“Seeing the effect of the Tongan volcano, which erupted thousands of kilometres away, was quite remarkable,” Stevens says. “It is also a reminder about just how connected our whole planet is. The climate is changing, and some key focal points are yet to be understood by science. But what is clear is that great changes are afoot – all the more if we don’t work together to change our greenhouse gas emissions.”
Julia Hager, PolarJournal
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