Subglacial lakes are some of the least researched and most important natural features on Earth. We also underestimated their prevalence and influence significantly.
Now more than 400 of these lakes have been found beneath the Antarctic continent. However, since the 1950s, scientists have found that this ice sheet does not contain any liquid water.
Now a similar story takes place in the northern hemisphere. New research has increased the number of well-known lakes lurking under the ice cover of Greenland 14 times, from only four recognized water bodies to a total of 60.
"This study gave us the first time to start an image of where the lakes are formed under the Greenland ice sheet," says lead author and hydraulic Jade Bowling from Lancaster University.
"This is important for determining their impact on wider hydrology and ice flow dynamics, and improving our understanding of the basal thermal state of the ice cover."
The Greenland ice sheet is more than a mile thick (about 1.9 miles) and it is still unclear what exactly happens under its frozen exterior. As the world continues to heat up, the frozen colossus loses about 244 billion tonnes of ice each year, and if the whole thing leaves it to dissolve, it can raise the sea level to 7 meters (23 feet).
Understanding the mole of water in the glacier is on its way from surface to bottom is therefore crucial for future climate models, and subglacial lakes are an important transitional station.
When these bodies are filled and tossed in Antarctica, they can cause a faster flow of ice, and scientists think that this could happen in Greenland. The study published last year, in fact, predicts that the chain reaction of drainage in Greenland could accelerate the flow of ice by as much as 400 percent.
But while mathematical models have predicted that the ice sheet of Greenland is home to thousands of these subglacial lakes, their finding is another story.
The first complete list of subglacial lakes appeared 56, and painstaking analysis required manual filtering of 500,000-kilometer airborne radio emission data, as well as changes in elevation of the ice surface, showing how these lakes swirling and releasing over time.
Unlike the Antarctic lakes, which can reach up to 11 kilometers, the subglacial lakes found in Greenland are much smaller, ranging from just 200 meters to nearly 6 kilometers. They are also generally stable and buried beneath relatively light ice, grouped around the edge of the ice sheet.
"In the center. T [Greenland ice sheet], the ice is largely frozen in its reservoir, and the water becomes predominant over the margins where glacial velocities are usually larger and greater hydraulic connection from the surface to the reservoir, "the authors wrote.
Somewhat less than half of these newly discovered lakes are active, which means that they are both leaving and full from changing the height of the ice surface. But, although they are now rare, reporters are concerned that these structures may become more frequent in the future.
As the climate continues to warm, surface water dissolved in Greenland may begin to form lakes and streams more in the ice cover, as is the case with Antarctica. When these water bodies drain to the bottom, scientists think they can reactivate & # 39; these subglacial lakes, reducing the overall stability of the ice cover.
"The result of increased water intake in the substrate at higher altitudes could open new pathways of subglacial drainage through improved slip and potentially link this dormant storage with the margin of the ice cover," the authors explain
At the edges of the glacial structure of Greenland, where melting is more rapid, the authors have noticed some evidence that this is already happening in two activated lakes.
"This" active "lake that fills and drains, making ice rising and falling, seems to be rare," BBC co-author Stephen Livingstone told Sheffield University.
"But we speculate that the signal of active subglacial lakes close to the edge of the ice cover can actually be lost, because the surface of the surface drops so much of the surface water."
In other words, the edges of the Grenland ice sheet might conceal even more of these dynamic subglacial lakes. As our world warms rapidly, the knowledge of where and how they can exist can make a difference.
The research was published in Nature Communications.