Antarctica's extremely salty Don Juan Pond

The fact likely refers to Don Juan Pond in the McMurdo Dry Valleys. Its calcium-chloride brine can contain about 40% salts by mass—roughly 18 times saltier than ordinary seawater—and remain liquid at temperatures near −50°C. But salinity varies, and “freezes only at −50°C” is not a precise fixed rule: that is an air temperature at which the pond can remain unfrozen. The illustration is AI-generated.