A team from the CSIC (Spain) recently published the first comprehensive description of how groundwater circulates in Antarctica, specifically in the freshwater lakes of Deception Island. These lakes, formed in closed volcanic craters, are connected to the ocean underground and even respond to tides, an unusual behavior in polar environments.
The work, led by Jorge Jódar from the Geological and Mining Institute of Spain (IGME-CSIC), was conducted during the Antarctic campaigns of 2024 and 2025. The results show that a significant portion of the meltwater and rain infiltrates the volcanic terrain, generating an annual recharge equivalent to 41% of the precipitation.
Functioning of the Aquifer System
The study describes two interconnected aquifers:
- Surface and seasonal: linked to the active layer of permafrost.
- Deep and permanent: circulates through highly permeable volcanic materials and connects directly with the sea.
The discharge from both aquifers controls the level of the lakes and explains why the water remains fresh, despite being in volcanic craters near the ocean.
Scientific Advances
The analysis includes the first estimation of the altitudinal isotopic gradient, which allows identifying the origin of the recharge water (snow and rain according to altitude). This helps to reconstruct water inputs, interpret climatic records preserved in the ice, and improve climatic and hydrological models in polar regions.
Deception Island combines active volcanism, glaciers, lakes, and permafrost, making it a natural laboratory for studying the interaction between freshwater and marine water in extreme environments.
Relevance for Climate Change
Understanding this system is key to anticipating how it might change with global warming and permafrost degradation.
The study provides a method applicable in other regions of Antarctica, expanding knowledge about water dynamics in volcanic polar environments.
Antarctic Lakes as Natural Laboratories
The lakes of Antarctica, especially subglacial ones like Vostok, are essential for:
- Studying past and future climate: the ice preserves air bubbles with atmospheres from hundreds of thousands of years ago.
- Exploring life in extreme conditions: microorganisms and unknown DNA have been found, useful as analogs for searching for life on Jupiter’s icy moons.
- Predicting sea level: active lakes influence the speed and movement of the ice.
- Freshwater reserves: they contain large volumes beneath the ice, part of the planet’s largest water reserve.
This finding represents the first comprehensive characterization of groundwater in Antarctica and opens new perspectives for understanding the interaction between freshwater and marine water in polar environments. Additionally, it reinforces the importance of Antarctic lakes as natural laboratories for studying climate change, extreme life, and ice stability.
