白令海表层沉积硅藻的种类组成与分布

SPECIES COMPOSITION AND DISTRIBUTION OF DIATOMS IN SURFACE SEDIMENTS OF THE BERING SEA

利用2010年中国第四次北极科学考察在白令海获取的7个站位的沉积物样品,分析了表层1 cm的沉积硅藻,共检出分属于38个属的101个硅藻种(含变种和变型),并编制了种类名录。这些种类可分为4个生态类群:(1)广温种;(2)北方温带种;(3)极地种;(4)海冰种。白令海西南海盆区以北方温带种占优势,主要有Neodenticula seminae,Thalassiosira trifulta,Rhizosolenia hebetata f.hiemalis、Actinocyclus curvatulus;而在东北陆架区以极地种为主,主要包括Fragilariopsis oceanica,Thalassiosira antarctica spora,Thalassiosira nordenskioeldii、Thalassiosira hyalina。海盆区沉积硅藻丰度最高,平均为3.7×106个/g湿重(不包括角毛藻休眠孢子);东部陆架区丰度最低,仅有0.7×106个/g。本文同时探讨了表层沉积硅藻分布与环境的关系。

A total of 101 diatom species （including varieties and forms）belonging to 37 genera were identified from six sur- face sediment samples collected in the Bering Sea during the Fourth Chinese Arctic Expedition. These species were sorted into four ecological groups： the eurythermal group, the boreal-temperate group, the polar group, and the sea- ice group. In the basin area, diatoms were dominated by the boreal-temperate group, and included Neodenticula semi- nae, Thalassiosira trifulta, Rhizosolenia hebetata f. hiemalis, and Actinocyclus curvatulus. However, in the northern shelf area, the polar group was dominant and the most numerous species were Fragilariopsis oceanica, Thalassiosira antarctica spore, Thalassiosira nordenskioeldii, and Thalassiosira hyalina. Maximum diatom concentrations of 3.6 × 10^6 cells per g of wet sediment were recorded in the basin and minimum concentrations of 0.7 ×106cells per g of wet sediment were found in the eastern shelf area, excluding resting spores of Chaetoceros spp. The relationship between the distribution of diatoms in surface sediment and environmental factors is discussed in this paper.