Although it may seem improbable, the surface of this lake is actually lower than sea level. Lake Vostok in Antarctica is buried under 4,000 metres of ice. The intense pressure created by this, alongside geothermal heat from the Earth’s interior, prevent the freshwater lake from freezing, even though its temperature is a chilly minus 3 degrees Celsius.

Located beneath Russia’s Vostok Station, Lake Vostok is one of the largest subglacial lakes in Antarctica. It was sealed off from the surface around 15 million years ago, but weirdly, it still has tides.

The surface of the lake rises and falls by around a centimetre, depending on the position of the Sun and the Moon.Lake Vostok is cold, dark, nutrient poor and pressurised, with unusually high concentrations of nitrogen and oxygen, yet despite this, there could be life.

In 2013, scientists detected microbial DNA in water samples taken from the lake. Some of the sequences matched those of known extremophiles, but others were new to science, suggesting the presence of some as yet unknown microbial species.

However, critics caution that the data could be artefactual, created by contamination from the icy drill used to reach the lake. So, for now, the jury is out. Only time will tell if there is life in Lake Vostok…

Top image: NASA