A recent discovery has the scientific community intrigued: a vast freshwater sea is trapped beneath Antarctica, specifically on Deception Island, connecting several underground lakes with the ocean.
This discovery, led by researcher Jorge Jódar, with the support of IGME-CSIC, could open the door to new water reserves in the not-so-distant future.
Deception Island, with its imposing volcanic and glacial landscape, harbors lakes seemingly isolated in craters. However, research has shown that these bodies of water feel the tides of the nearby ocean, challenging the traditional perception of these lacustrine systems.
The study reveals that the permeable volcanic terrain allows rainwater and meltwater to filter quickly, which is crucial in an environment where 41% of the annual precipitation contributes to recharging the aquifer. This infiltration rate is remarkably high for a polar ecosystem.
In terms of hydrogeology, researchers have identified two interconnected aquifers on the island. The first, more superficial, is related to the active layer of the permafrost, while the second, deeper one, is directly connected to the ocean. This underground connection explains the fluctuations in the lakes level despite their apparent isolation.
One might wonder why saltwater does not invade these lakes. The answer lies in the flow of freshwater from the island’s interior, which acts as a natural barrier, preventing the entry of seawater and keeping the lakes’ content fresh.
A sea of freshwater
This phenomenon underscores that Antarctica is not merely a static ice landscape. The interaction between precipitation, meltwater, and aquifers is dynamic and crucial for understanding the impact of climate change. Variations in annual precipitation and meltwater directly affect this delicate balance.
In addition to analyzing water levels, scientists have developed a tool that relates the isotopic composition of precipitation with altitude, offering clues about the origin of the water recharging the aquifers. This advancement is vital for improving the accuracy of climate models in polar regions.
The research, conducted during the 2024 and 2025 campaigns, is a testament to the team’s dedication in extreme conditions. Their findings, published in the bulletin of the IGME-CSIC, provide a new understanding of these unique ecosystems and their response to global warming.
