Table 1.

Post-freeze survival and data obtained from differential scanning calorimetry on H. crispae from Vellerup Vig, Denmark (20 ppt) in the active and P1 stages

SamplePost-freeze survival (%) (frozen for 24 h)Post-freeze survival (%) (frozen for 36 days)Crystallization temp. (°C)Melting temp. (°C)Water content (%)Body-water frozen during freezing exotherm (%)Osmolality of extracellular fluids (mOsm kg–1)
Pseudosimplex 153.3±15 (6)12.7±7 (6)–19.6±3.1 (6)–4.29±0.79 (5)67±4 (5)59±3 (4)928±77 (5)
Active0 (6)0 (6)–21.6±2.1 (3)–4.48±0.15 (3)68±4 (3)69±5 (3)975±36 (3)
t-test (P<0.05) * * NSNSNS * NS
  • All values are expressed as means ± s.d. Parentheses indicate the number of replicate groups examined, each group containing 40–75 animals. The first column refers to the type of cyclomorphic stage investigated. Second and third columns show the survival following cooling to– 20°C at 1°C min–1 for 24 h and 36 days, respectively. The temperatures in the fourth and fifth columns are the onsets of the peaks as calculated by the DSC 7 software. Water content was determined gravimetrically using the equation: (wet mass – dry mass)/wet mass. Ice content (seventh column) was calculated using the water content and the enthalpy (ΔH) of the freezing exotherm. The final column indicates the osmolality of the extracellular fluids determined by melting point depression. Significance level was P>0.05 (NS, not significant), P<0.05 (*, significant)