南极普里兹湾微量元素沉积地层记录及其来源、通量和浮游植物群落的生态响应

In the Southern Ocean of high nutrients low chlorophylla regions, trace metals play a key role in regulating phytoplankton productivity; trace elements limitation is the main explanation for HNLC. Trace metals are also important tracers for water mass, paleoproductivity, lithological inputs, and historic pollution inputs. However large knowledge gaps remain in the biogeochemical cycling of trace metals in these areas，especially in the resource,fluxes and background of trace metals and their influence on the phytoplankton biomass and srtucture..This proposal is applied to reconstruct the trace metals records in the sediment cores of hundreds of years，study trace metal fluxes and seasonal changes.Combining with the biological elements, such as organic carbon and biological silicon, and lithological element Alumium in the sedimental cores and particulate fluxes, the importance of biological resource and lithological resource of the trace metals in the Prydz Bay will be discussed; according to the phytoplankton biomarker such as brassicasterol and dinosterol in the sedimental cores, phytoplankton biomass and their structure of dominant species ( diatom and dinoflagellate ) during sedimentation will be revealed, in order to reconstruct the interaction and response between trace metals and phytoplankton variable. The emphasis is the influence of trace metals on the phytoplankton biomass and structure, and its response to the climate and environmental changes in east Antarctica.

微量元素在南大洋浮游植物生产力调节方面发挥着重要作用，微量元素限制是解释南大洋HNLC现象的主流观点。微量元素也是指示水团交换、古生产力、岩源输入及历史性污染输入的重要指标。但是目前对南大洋，尤其是普里兹湾微量元素来源、环境背景值、通量及其对浮游植物营养过程中作用的认识还存在着巨大的知识缺口。.本项目拟建立普里兹湾微量元素Cu、Pb、Zn、Cd、Cr、Co百年尺度的沉积地层记录，利用浮游植物标志物反演浮游植物生物量及其群落结构与微量元素之间的互动响应，探讨微量元素对东南极地区气候环境变化的反馈。通过时间序列沉积物捕获器研究微量元素沉降通量及其季节性变化，并将沉积物和沉降颗粒物有机结合，通过生源要素OC、BSi和地壳元素Al（Ti或Li），探讨生物源性和岩源性输入在普里兹湾微量元素来源中的比重关系。

南大洋的“生物泵”在全球二氧化碳循环和气候变化中扮演着重要的角色，而微量元素则是南大洋海洋初级生产力及其“生物泵”的主要调控因子；同时，微量元素也是示踪水团、追溯物源和反演海洋生产力的重要指标。但是南大洋，尤其是中国南极科考的重点海域普里兹湾鲜少有相关的报道。本项目通过对普里兹湾不同海区具有代表性的沉积物柱状样、陆架区沉降颗粒物、陆架区提纯的硅藻蛋白石中微量元素的检测，获取了普里兹湾微量元素含量、通量、时空分布特征的背景值数据，分析了微量元素的来源及其组成，研究了利用不同的微量元素以及蛋白石中Zn/Si比值反演海洋生产力的可能性，并成功利用沉积物捕获器获取的长时间序列参数Ba建立了反演普里兹湾边缘海输出生产力的模型。