This study focused on radiolarian diversity in the deep-sea sediments of the East Indian Ocean (EIO) to demonstrate their potential as a paleoceanogrpahic proxy. Radiolarians are in general abundant in deep-sea sediment of the EIO. However, around Sri Lanka, their abundances decrease potentially because of terrigenous matter inputs. The significantly high abundance of radiolarians in the northern Ninety-East Ridge (NER) area may indicate high levels of productivity in the overlying waters. Further, redundancy analysis (RDA) demonstrated that, in the EIO, Tetrapyle group and Phorticium group mainly inhabited the water depth between 25 m and 100 m; Acanthodesmia vinculata, Botryostrobus scutum and Dictyocoryne group can potentially be a nutrient indicator; the distribution of Didymocryrtis tetrathalamus tetrathalamus may possibly be related to the dissolved oxygen concentration; the distributions of Cornutella profunda, Cycladophora sp., and Cycladophora cornuta may be mainly influenced by flows of AAIW. Our analysis documented that the distribution of an Equatorial Undercurrent (EUC) assemblage, including A. vinculata, B. scutum, Dictyocryphalus hispidus, D. tetrathalamus tetrathalamus, Tetrapyle group, Phorticium group and Dictyocoryne group, may be controlled by the eastward-flowing EUC with the salinity-high and dissolved oxygen-rich waters. The Antarctic Intermediate Water may also affect the distribution pattern of Intermediate-Deep assemblage, including Cycladophora sp., C. profunda, Clathrocanium diadema and C. cornuta, with a possible northward spread along the NER into the southern Bay of Bengal.

这项研究的重点是东印度洋 (EIO) 深海沉积物中的放射虫多样性，以证明它们作为古海洋生物代理的潜力。放射虫在 EIO 的深海沉积物中通常很丰富。然而，在斯里兰卡周围，由于陆源物质输入，它们的丰度可能会下降。九十东海脊 (NER) 北部地区放射虫的显着丰度可能表明上覆水域的生产力水平很高。此外，冗余分析（RDA）表明，在EIO中，Tetrapyle组和Phorticium组主要栖息在25 m至100 m的水深之间；Acanthodesmia vinculata，Botryostrobus盾牌座和Dictyocoryne组可能是一个营养指标；Didymocryrtis tetrathalamus tetrathalamus的分布可能与溶解氧浓度有关；Cornutella profunda、Cycladophora sp.和Cycladophoracornuta的分布可能主要受AAIW流量的影响。我们的分析记录了赤道暗流 (EUC) 组合的分布，包括A. vinculata、B. scutum、Dictyocryphalus hispidus、D. tetrathalamus tetrathalamus、Tetrapyle组、Phorticium组和Dictyocoryne组, 可能受东流的 EUC 控制, 具有高盐度和富含溶解氧的水域。南极中层水也可能影响中间体深组合的分布格局，包括Cycladophora属，C.股深，Clathrocanium迪亚德马和C.枸骨，沿NER到南部孟加拉湾的一个可能向北蔓延。