冲绳海槽中部表层沉积物中的放射虫

1992年7月“向阳红16号”海洋调查船利用大洋50型抓斗在冲绳海槽中部（25°30’－30°N，125°－129°E）区域内获取表层沉积物样品88个。表层沉积物中的放射虫定量分析结果表明；愈近海槽放射虫的数量及属、种丰度值愈高，西侧槽坡离开槽区越远，放射虫数量及属种越渐少。而东侧槽被放射虫数量则表现了高、低值成点状分布的格局。表层沉积物中两大类放射虫的百分含量分别为泡沫虫约占87％，罩笼虫约占13％。另外根据分析结果，把本区分为3个小的沉积区：陆坡上部沉积区；陆被下部沉积区；海槽底部沉积区。

RADIOLARIA FROM THE SURFACE SEDIMENTS IN THE MIDDLE OKINAWA TROUGH

The Okinawa Trough is a part of the East China Sea. Scientists have studied the trough and have achieved a lot In this paper, the numbers of radiolaria, the distribution of genera and species, the division of radiolaria and the con-elation among the radiolaria shells, and the sediments and the water are systematically studied, using 88 surface sediment samples with the quantitative analysis collected by R/V Xiangyanghong 16 from the middle part of the Okinawa Trough (25°30'N to 30°N, 125°E to 129°E) in July 1992, together with historical data. The results show that in this area, the quantity and the abundance of genera and species for the shells of radiolaria in the surface sediments are high near the Okinawa Trough. The radiolaria are present in different quantities on the eastern slope of the Okinawa Trough, where the bottom is rugged and rough. Radiolaria shells are mainly Spumellaria and account for 87% of the total shell quantity; Nessellaria amount for 13% in the surface sediments. There is a difference between the trough and its two sides. The Spumellaria content is relating large near the slopes, whilst the Nessellaria content is relatively high in the trough. The distribution of radiolaria in the surface sediments is closely related to water temperature, water depth, salinity and current. At the same time, it is influenced by sediment composition and grain size. Based on the analysis, this region can be divided into three sediment areas: the upper continental slope; the lower continental slope; and the central trough.