Hungarian researchers say that during harsh martian winters, when temperatures plummet to minus 200 degrees Celsius (minus 328 Fahrenheit), these so-called Mars Surface Organisms are protected by a thick blanket of ice which then melts as the planet’s early summer temperatures climb to just above zero. Large grey dark dune spots — with a diameter ranging from 10 meters (33 ft) to several hundred meters — are left behind. The Hungarians claim the spots are dried-out organisms which can reactivate themselves once the colder, icy season sets in again.