东北印度洋末次冰盛期以来放射虫的时空分布及其环境变化响应

东北印度洋在典型季风气候和多个中深层水团影响下形成了独特的海表盐度变化和区域深水环境。硅质生物放射虫在深海古海洋和古气候研究中发挥着不可替代的作用。本课题拟通过东北印度洋上层水体、表层沉积物和钻孔柱状样的综合研究，揭示现代放射虫的区域分布、深度习性和年际变化，探讨其与上层海洋环境变化的关系；比较近代沉积放射虫与现代放射虫的关联程度，分析放射虫沉降与埋藏保存的影响控制因素；揭示末次冰盛期以来放射虫时空分布及其对海洋环境（如季风、温盐和水团等）变化响应的机制；比较不同区域的钻孔柱状样，尝试重建末次冰盛期以来海洋环境尤其是水团的动态演化特征；阐明东北印度洋与南海南部的区域差异与共性，核实并建立一套与热带低纬度海洋环境演化相适应的替代指标。研究成果不仅将填补空白、增进新认识，而且将为热带低纬度海域古环境和古气候研究提供新证据和新思路，为深海沉积、区域环境及其全球变化响应研究提供重要的基础科学资料。

Under the influence of typical monsoonal climate and several intermediate and deep watermasses, the northeastern Indian Ocean has unique surface salinity contrast and regional deep water environment. Siliceous radiolarians play an irreplaceable role in the deep-sea paleoceanography and paleoclimatology construction. This project is aimed to comprehensive analyze the radiolarians from upper water, surface sediment and down-core sediment, to reveal the regional distribution, living depth and interannual variation of modern radiolarians and their relations with upper ocean environmental change. By analyzing the degree of correlation of radiolarians in recent deposition with those in modern water, we will decipher radiolarian sedimentation and burial preservation and their controlling factors. We will reveal the temporal and spatial changes of radiolarians since the Last Glacial Maximum in the northeastern Indian Ocean and their responses to environmental variables (such as monsoon, temperature, salinity and watermass). Based on the comparison of down-core data among several regions, we try to construct the dynamic evolution characteristics of marine environment, especially watermasses since the Last Glacial Maximum. We will compare the differences and similarities between the northeastern Indian Ocean and the southern South China Sea, to verify and establish a set of alternative proxies for indicating special marine environment which has regional suitability in the tropical low-latitude ocean. Results from this project will fill the gaps and increase new knowledge of regional radiolarians, which will provide new evidence and new method for further recovering evolution histories of paleoenvironment and paleoclimate, and even give some important basically scientific data for further study the deep-sea sediment, regional environment and their responses on global change.