Survival at low temperatures was studied in three species of Tardigrad
a from Muhlig-Hofmannfjella, Dronning Maud Land, Antarctica. Both hydr
ated and dehydrated specimens of Echiniscus jenningsi, Macrobiotus fur
ciger and Diphascon chilenense had high survival rates following expos
ure to -22 degrees C for ca. 600 days, and dehydrated specimens follow
ing 3040 days at this temperature. In hydrated E. jenningsi, mortality
increased with the duration of exposure from 7 to 150 days at -80 deg
rees C, while mortalities of the two other species did not change. Hyd
rated specimens of all species were rapidly killed at -180 degrees C,
but all species exhibited good survivorship in the dehydrated state af
ter 14 days at -180 degrees C. In conclusion, hydrated tardigrades are
able to survive extended periods at low temperatures, and dehydrated
specimens are even better adapted to survive overwintering on Antarcti
c nunataks.