Abstract:

Diatoms in 22 surface sediment samples from the northwestern sea area of Antarctic Peninsula are studied. 82 species of diatoms are examined. The maximum abundance of diatoms ( > 50000 / g) were found in both the middle part of the Bransfield Strait and the deep sea area northwest of the South Shetlands. Medium abundance of diatoms (6000-50000 / g) is observed in the samples from the shallow area of Maxwell bay, the southern sea area of Livingston Island and northwestern shore zone of the Antarctic Peninsula. Low content of diatoms ( < 6000/g) was found in shallow sea area of South Shetlands and northern sea area of Parmer Islands. According to their abundance and ecological charcteristics the diatoms can be divided into three assemblages: 1. Thalassiosira antarctica-Charcatia actinochilus-Eucampia Balaustium. 2. Th. antarctica-Nitzschia kerguelensis-Coscinodiscus lentiginosus. 3. Cos. lentiginosus-E. balaustium -Nitzschia kerguelensisi-Schimperilla antarctica. On the basis of comparison of diatoms in the surface sediments with diatoms in the water and hydrodynamic condition as well as dissolution of diatoms, the sedimentation of the diatioms is discussed in this paper.