Scientists from Hokkaido University, University of Oslo, Utrecht University, and Norwegian Polar Institute found a possible river fed by melting ice underneath the ice sheet of Greenland that spans a 620-mile (1000 km) route.
The discovered river is said to be flowing through an entire length of a subglacial valley, ending at the Petermann Fjord. The research was published in the journal The Cryosphere.
The Dark River is still not proven, but it most probably exists
While the "Dark River" is probably there, there is still some uncertainty which largely stems from the significant gaps in the radar data of Greenland's ice sheet.
One of the study authors Christopher Chambers, a scientist at Hokkaido University’s Institute of Low Temperature Science, said "The data gaps are filled by interpolation, which involves taking data from nearby grid points." He added, "The method used tends to fill valleys because it takes information from surrounding grid points which will be mostly not in the valley."
"Essentially wherever a plane has crossed the path of this valley, it has detected it, and this is along a more than 1000 kilometer route, so there is currently no solid evidence to suggest that it is actually blocked," Chambers said in the press release.
Previous studies indicated that there could be trenches, valleys, or canyons underneath the large ice sheet of Greenland, and the researchers did not know whether these structures were connected to each other or not.
Melting water flows underneath the ice
However, this recent study adds more to the indications since the team found that the melting water of Greenland flows beneath the ice, bringing to mind the question of whether there might be a riverbed under all that ice.
Chambers and his team came up with a ‘thought experiment’ and they investigated the hypothesis that the valleys aren’t broken up but instead flow as a giant river, by simulating the state of Greenland using the SICOPOLIS method (SImulation COde for POLythermal Ice Sheets).
"Our simulations did not indicate a large effect on the overall ice sheet movement or sliding, so it may not have a huge impact despite being very long," Chambers explained. "However, it is possible that it could have a greater impact as it takes water away from one region and dumps it in another and we may not have simulated this well due the inevitably simplified nature of our subglacial water modeling."
While these findings are hypothetical for the time being, the team is confident that once they get newer data after studying the aerial surveys of the ice sheet topography, they'll be able to come up with more accurate simulations of the Dark River.