北极楚科奇海及其附近海域海底底栖贝类遗壳分布

对采自北极的23个站的底栖贝类遗壳进行鉴定,结果表明这些贝类遗壳计有17个种,其中双壳纲13种,腹足纲4种.根据鉴定到种的13个种可将所鉴定的软体动物分为两个区系:北极和环北极寒温带种,它们是Astarte montagui,Liocyma fluctusa,Macoma calcarea,M.moesta alas-kana,Mya pseudoarenaria,Nuculana pernula,N.radiata,Nucula bellotii,Serripes groenlan-dicus和Turritella polaris,共计10种,它们是北极水域软体动物区系组成中的主要成分;北极北太平洋寒温带种,它们是Argobuccinum oregonense,Cyclocardia crebricostata和Trichotropis cor-onata有3种.根据食性又可将它们分成滤食性、肉食性和碎食性三种,其中摄食沉积物中有机碎屑的碎食性种类占优势,包括双壳类中的Macoma calcarea,M.moesta alaskana,Macoma sp.,Nuculana pernula,N.radiata,Nucula bellotii,和腹足类的Trichotropis coronata,共计7种,它们不仅种类多,丰度高,而且在调查区的分布同细颗粒的沉积物有密切关系.

Distribution of molluscan remains in the sediment of the Chukchi Sea in the Arctic and its vicinity

The results of an analysis of molluscan remains collected from the Chukchi Sea,the Beaufort Sea and the Bering Sea during the first Chinese national arctic research expedition,from July to September 1999.Seventeen species of molluscs have been identified,and they belong to two classes: Bivalvia and Gastropoda.The compositions of Mollusca from the above mentioned areas are very simple.According to the distribution pattern,among the molluscan species two groups may be distinguished.The panarctic and circumboreal group comprises Astarte montagui,Liocyma fluctuosa,Macoma calcarea,M.moesta alaskana,Mya pseudoarenaria,Nuculana pernula,N.radiata,Nucula bellotii,Seripes groenlandicus and Turritella polaris.Three species,Argobuccinum oregonense,Cyclocardia crebricostata and Trichotrois coronata are components of the panarctic and Pacific boreal group.With regard to feeding habits,detritus feeders dominate.There are seven species of detritus feeders,i.e.,Macoma calcarea,M.moesta alaskana,Macoma sp.,Nuculana pernula,N.radiata,Nucula bellotii and Trichotropis coronata.Detritus feeders are dominant with regard to the numbers of species as well as to the occurrence frequency.Macoma calcarea is the most abundant species.