Experimental Evidence for Non-encysted, Freeze-resistant Stages of Terrestrial Naked Amoebae Capable of Resumed Growth after Freeze-thaw Events

Experimental evidence is presented to support a hypothesis that terrestrial naked amoebae, collected during late autumn from cold, moist temperate soil, develop a non-encysted, freeze-thaw resistant stage that is capable of surviving winter frozen soil. Therefore, in addition to cyst formation, naked amoebae may survive harsh, frozen winter soil in a dormant or resting stage that is capable of rapid resumed growth in spring, thus gaining an immediate competitive advantage in exploiting food and other environmental resources early after the winter thaw.