东南极洲中山站附近1年生海冰的发育和结构特征及其对生物群落的影响(英)

Sea ice growth, characteristics and ice algal biomass were measured at four sites off Zhongshan Station (66°22, 24" S, 76°22, 40" E), East Antarctica in 1992. The ice formed in late March,grew stablely and reached its highest thickness of 174 cm in November and December. The difference　between measured ice thickness and the calculated values from the classical Stephen formula are small,suggesting that the heat flux from the ocean to the underside of the ice at this area is not obvious.The results of sea ice analysis show that the sea ice consists mainly of congelation ice, and the frazil　ice only occurs at the top of sea ice, no snow or platelet ice is found. When the ice thickness reached its　　highest values in late spring, congelation ice contained average 89. 5 % of the total column crystal 　structure, the remaining 10. 5% consisted of frazil ice, and the ice thicknesses above the congelation ice layers were mostly consistent throughout the year, suggesting that the sea ice developed in a relativelycalm environment after the top layer of ice had formed and grew downwards only.Congelation ice fabrics shows frequent moderate to strong alignments at almost all depths, and thedegree of preferred orientation mostly increased with depths. In the sub--structure of congelation ice,the plate width are in a range of 0. 55 to 1. 05 mm with an average value of 0. 76 mm. No apparent pattern occurs in its vertical profiles.Ice crystal composition is one of the major factors influencing the ice algal biomass, and the effectsof crystal alignments and ice plate width of congelation ice are not apparent.

Developing and Structural Characteristics of First-Year Sea Ice and With Effects on Ice Alage Biomass of Zhongshan Station,East Antarctica