冲绳海槽表层沉积物放射虫属种空间分布特征及其影响因素  

Spatial distribution characteristics of radiolarian species in surface sediments from the Okinawa Trough and the impact of environmental factors

作　　者：董智 石学法 邹欣庆 邹建军 杨宝菊 刘季花 程振波 DONG Zhi;SHI Xuefa;ZOU Xinqing;ZOU Jianjun;YANG Baoju;LIU Jihua;CHENG Zhenbo(Collaborative Innovation Center of South China Sea Studies and Ministry of Education Key Laboratory for Coast and Island Development,Nanjing University,Nanjing 210023,China;Ministry of Natural Resources Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266061,China)

机构地区：[1]南京大学中国南海研究协同创新中心与海岸与海岛开发教育部重点实验室,江苏南京210023 [2]自然资源部第一海洋研究所自然资源部海洋地质与成矿作用重点实验室,山东青岛266061 [3]青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室,山东青岛266061

出　　处：《地学前缘》2020年第6期300-312,共13页Earth Science Frontiers

基　　金：“全球变化与海气相互作用”专项项目(GASI-GEOGE-04);青岛海洋科学与技术试点国家实验室鳌山科技创新计划项目(2016ASKJ13);国家自然科学基金项目(U1606401);国家重点基础研究发展计划“973”项目(2013CB429704);中德合作项目(03F0704ASIGEPAX);泰山学者项目。

摘　　要：为探究冲绳海槽放射虫属种的空间分布特征及其海洋学意义,对采自冲绳海槽北部、中部和南部3个海域的34个表层沉积物中的放射虫群落组成特征进行了系统研究。总体看来,冲绳海槽表层沉积物放射虫丰度较高,群落组成以热带亚热带暖水放射虫属种为主,其中优势种为Tetrapyle octacantha group、Spongodiscus resurgens和Euchitonia furcata。结果表明冲绳海槽放射虫属种存在明显的区域差异性,除T.octacantha group以外,其余暖水指示种含量总体上均呈现南高北低的变化趋势。冲绳海槽北部陆架陆坡区受长江冲淡水的影响,温度和盐度变化较为剧烈,因此可能不利于大多数放射虫暖水指示种的发育,但T.octacantha group却因自身适宜生存的温度范围较大,进而得以在冲绳海槽北部陆坡区呈现出高值。较高的中层水温度可能是抑制亚北极中层水指示种Cycladophora davisiana在冲绳海槽分布的主要因素,而冲绳海槽的高海槛则限制了太平洋深层水种Carpocanistrum papillosum和Cornutella profunda的入侵。冲绳海槽放射虫的空间分布对区域海洋环境特征有着很好的响应,因此可以为古环境重建研究提供重要依据。We systematically analyzed the newly collected radiolarian assemblages data from 34 surface sediment samples that span the northern,middle and southern Okinawa Trough to better understand the regional species compositions and distribution range.Our study provided the first detailed regional characterization on the modern distribution patterns of radiolarian species under varying temperature,nutrient,and water depth.The results showed that diverse subtropical species dominated the radiolarian assemblages in all samples.The most abundant species was Tetrapyle octacantha Müller group(23%),followed by Spongodiscus resurgens and Euchitonia furcata.Variation in the radiolarian assemblages in different parts of the Okinawa Trough could reflect the differences in the overlying water masses.In general,the relative abundance of warm-water species decreased with increasing latitude.However,the distribution pattern of the T.octacantha group showed an opposite trend with high abundance in the western continental slope of the northern Okinawa Trough.The northern Okinawa Trough near the East China Sea continental shelf is strongly affected by the Changjiang diluted water,resulting in large seasonal variations of temperature and salinity.The T.octacantha group has been found to have stronger tolerance to relatively lower temperature and thus is able to become the dominant species in the northern Okinawa Trough.In this study,the depth-related distribution of radiolarians in the Okinawa Trough was also investigated.The lower abundances of Cycladophora davisiana and Actinomma leptodermum,which are the mid-water species in the Okinawa Trough,may be partly related to the impact of higher mid-water temperature.Another factor that may affect the distribution pattern of deep-water dwellers in the Okinawa Trough is the inhibition effect of shallow straits on the Pacific deep water intrusion.

关 键 词：放射虫 黑潮 温度 表层沉积物 冲绳海槽 

分 类 号：P736.2[天文地球—海洋地质] P722.6[天文地球—海洋科学]