Freeze induced glucose accumulation in the enchytraeid, Fredericia ratzeli from Greenland.

The tolerance of freezing and associated accumulation of cryoprotectants was studied in an Arctic population of the enchytraeid Fredericia ratzeli. At -3 and -5 degrees C specimens readily froze when slowly cooled in contact with moist soil. A small fraction of the animals (10-20 %) survived internal ice formation under these circumstances. Frozen specimens had elevated glucose concentrations as compared to unfrozen control animals acclimated at 0 degrees C. In a fraction of the animals, equal to the fraction surviving freezing, a high concentration of glucose was detected. The highest values amounted to ca. 150 microg mg(-1) dry weight, corresponding to ca. 270 mmoles L(-1). It is argued that the physiology of freeze tolerance in this enchytraeid resembles the physiology described for freeze tolerant earthworms and frogs.