There are only a few places on Earth where ecosystems have been allowed to evolve for thousands of years in isolated conditions. One of those places in underneath the thick ice of Antarctica, where researchers have uncovered ancient microbes in isolated glacial lakes. This week, a new study has shown that sudden flooding has eliminated one of those lakes.

The European Space Agency’s CryoSat satellite has located a large “crater” in the midst of Antarctica. Researchers believe the crater was left empty after a lake buried under 3 km (around 1.8 miles) of ice suddenly disappeared. Using data from CryoSat and NASA’s ICESat, European scientists have now been able to map the crater. The research has been published in the journal Geophysical Research Letters.

“Thanks to CryoSat, we can now see fine details that were not apparent in older satellite data records,” said Malcolm McMillan, lead author of the study and an environmental researcher at the University of Leeds.

The new data shows that six cubic kilometers (1.5 trillion gallons) of water drained from the crater from 2007 to 2008. With the ESA describing this volume as roughly the amount of water in Loch Ness, the event is the largest of its kind ever recorded. Though the lake has been refilling since 2008, researchers have stated it could take decades for the lake to refill completely.

“It seems likely that the flood water – and any microbes or sediments it contained – has been flushed into the Southern Ocean, making it difficult to imagine that life in this particular lake has evolved in isolation,” said Andrew Shepherd, a co-author of the study and a professor of Earth observation at the University of Leeds.

(Image via ESA/AOES Medialab)