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

The tolerance of freezing and associated accumulation of cryoprotectants wa s studied in an Arctic population of the enchytraeid Fredericia ratzeli. At -3 and -5 degreesC specimens readily froze when slowly cooled in contact w ith moist soil. A small fraction of the animals (10-20%) survived internal ice formation under these circumstances. Frozen specimens had elevated gluc ose concentrations as compared to unfrozen control animals acclimated at 0 degreesC. In a fraction of the animals, equal to the fraction surviving fre ezing, a high concentration of glucose was detected. The highest values amo unted to ca. 150 mug 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 .