The team established a temporary research station at this remote site, complete with an airstrip and tent accommodation for 26 people, taking advantage of the Antarctic summer's 24-hour daylight and relatively mild conditions of -10 C and light winds. Using a hot water drilling system, they bored a 500-meter-deep hole through the ice, revealing water and sedimentary rock beneath the ice sheet.
The borehole, with a 30 cm diameter, enabled the team to lower cameras and scientific instruments to observe the conditions at the base of the ice stream. "We struck water at the end of the borehole and, with the help of our camera, we even discovered a school of lobster-like creatures, 400 kilometers from the open ocean," said expedition leader Huw Horgan, who is currently conducting research at ETH Zurich and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL.
This discovery confirms long-held theories about subglacial water flow, where geothermal heat and other factors create hidden lakes beneath the Antarctic ice caps. These watercourses remain largely mysterious, but the borehole at the Kamb Ice Stream marks a critical step towards understanding how these systems function.
The team's measurements revealed that the subglacial water channel is approximately 100 by 200 meters in cross-section. However, contrary to previous models, the flow is relatively slow, with only a small amount - less than one cubic meter per second - of fresh water moving toward the sea. "This amount of water is much smaller than what the existing models had predicted," Horgan explained.
Additionally, their findings indicate that these subglacial watercourses do not flow continuously. Instead, they operate in cycles, likely fed by upstream subglacial lakes that periodically empty, sending significant floods toward the sea. Sediment analysis from beneath the ice stream suggests that these major flood events occur roughly every decade, with smaller, yet unmeasurable, events potentially happening in between.
Understanding these subglacial flows is crucial for predicting the future stability of the Antarctic ice sheets, which play a critical role in global sea level regulation. The Ross Ice Shelf and other such formations act as natural barriers, slowing the flow of glaciers into the ocean. Their stability is essential for mitigating the impacts of global warming and the resulting sea level rise.
Looking ahead, Horgan and his colleagues plan to return to the Antarctic during the 2025/2026 summer season to collect long-term data on these subglacial processes, focusing on how they respond to warmer climatic periods, a critical factor as the planet continues to warm.
Research Report:A West Antarctic grounding-zone environment shaped by episodic water flow
Related Links
ETH Zurich
Beyond the Ice Age
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