Beneath the vast glacial surfaces of the Antarctic is a network of large rivers and lakes. Antarctic ice sheets act as an insulating coating, helping to trap heat from the ground and the low heat generated by ice deformation, which prevents the water of Antarctic rivers and lakes from freezing.
On the other hand, the flow of water under the ice sheets reduces the friction of their subsurface, and as a result, these plates move hundreds of meters in the ocean every year. When the water of the subterranean rivers reaches the end of its course, it moves upwards and appears on the surface of the ice sheets. Eventually, these waters enter the cold, salty cavities beneath the icy platforms, which are actually the edges of the ice sheets that surround the Antarctic. At this stage, river water combines with ocean water and releases nutrients and sediment. These materials cause the bottom of the ice rigs to melt and may separate them from the ice sheets. This is important because ice rigs actually act as a barrier between water and large Antarctic ice sheets, preventing them from moving.
Predicting the rate of change of this process in the coming decades can play an important role in our understanding of the phenomenon of rising ocean water levels. Unfortunately, so far little research has been done on the Antarctic and the rivers that flow beneath it.
The New Zealand Antarctic Science Platform project is one of the first serious efforts to study the subterranean rivers in Antarctica. Researchers in Antarctica have previously found that rivers that flow under Antarctic glaciers form estuaries or ponds that enter the oceans 500 meters below the ice sheet and 500 kilometers from open water.
Explore the subterranean rivers
New Zealand explorers recently published the results of their research after visiting the Kamb ice sheet on the Antarctic ice sheet. This huge river of water and ice is located on the other side of the Twice’s ice sheet. The flow of the Komb River has been very high in the past centuries, but since 160 years ago, due to changes in the distribution of water under the icy surfaces, the flow rate of this river has decreased.
The Combe current has so far been immune to the effects of global warming and can partially make up for some of the ice lost in other parts of Antarctica. Thus, the study of changes in the flow of the Combe River can reveal the early signs of a change in the state of the Antarctic ice sheets and the oceans beneath them.
One of the great challenges for researchers in this field is the high impact of ice sheets on external variables. Rising ocean temperatures are causing changes in the behavior and properties of ice sheets, but other events are also causing such changes, which could make it difficult for researchers to study the effects of climate change on Antarctica. One of these external events is subsurface floods. These floods occur when the ice breaks the edge of a subterranean river or lake. Due to the sudden entry of a large amount of ice into a river or lake, the speed of water flow changes and causes flooding. Predicting the time of such an event is fundamentally difficult, so it makes it difficult for scientists to distinguish the effects of such an event on ice sheets.
The start of Corona globalization has negatively affected Antarctic research programs, disruption of the global supply chain and delays in equipment delivery have left research teams behind in their schedules.
Last summer, the New Zealand government rebuilt one of its main research stations in Antarctica Scott Center (Scott base) started. The country is working to develop the infrastructure needed by scientists to travel long distances across Antarctica. The Combe Research Group was one of the first teams to benefit from the New Zealand Government’s new initiatives. The group camped for several months, 900 kilometers from New Zealand’s permanent station in Antarctica.
Doing research in harsh Antarctic conditions, such as piercing thick polar ice caps and holding them open, requires great skill. The Combe group did this by spinning hot water inside a hole a few hundred meters away. After reaching the desired location and setting up the camp, the explorers made a hole 500 meters deep and 0.4 meters in diameter and kept it open for two weeks. Researchers were thus able to sample and gather evidence for a wide range of scientific projects.
The New Zealand scientists’ ten-year effort came to fruition when Team Combe was able to pinpoint the exact location of the source of the river deep in Antarctic ice. Studies conducted through the drilled hole showed that the river is 240 meters high and less than 200 meters wide. 200 meters wide may seem like a big deal to one river, but it is small compared to the width of other Antarctic rivers. Also, the width of the Komb River was less than the value estimated from the surface mapping.
One of the disadvantages of using a hole drill in ice is that you limit yourself to studying a fixed location. To overcome this limitation, Cornell University researchers used a submarine robot to explore deep beneath the ice. One of the researchers’ discoveries when photographing water beneath the ice surface was the presence of large groups of amphibians. The discovery puzzled researchers for some time, as the animals became so crowded that they initially thought there was a problem with the filming equipment.
In the end, the researchers had to deploy anchor-like devices in the ocean beneath the ice surface. This device will transmit ocean conditions to the base in the coming years by continuously monitoring the groundwater. Just five days after the device was launched, the team was able to detect the eruption waves of the Tonga volcano in the Pacific Ocean.
Apart from routine studies, identifying such events increases the motivation of group members to use such equipment. In the coming years, scientists will be able to closely monitor the changing state of Antarctic subsurface currents, including possible floods, relying on state-of-the-art equipment.