Palynological tracers of ocean and climate changes

本方案有两个主要组成部分。其中一个涉及气候-海洋系统的一个关键要素：北极和北大西洋之间的联系及其对大规模海洋环流变化的影响。另一个是方法学，涉及利用海洋沉积物中的藻类化石（甲藻孢囊=甲藻孢囊）重建高纬度水文条件的变化。该研究的最终目标是对过去200万年来的气候和海洋概况进行尽可能最好的重建，特别关注温暖的事件，以支持预测气候-海洋建模工作。因此，将对长期沉积记录进行研究，以确定北极没有常年海冰的区间，并评估海冰和格陵兰冰量减少对北大西洋西北部气候和海洋环流的影响。将对跨越目前间冰期（过去11 000年）的沉积物岩心进行详细分析，以研究北极海冰和北大西洋西北部水文地理的自然变化，并探讨北极海冰生产与淡水融水输出到北大西洋之间的千年节奏和联系。最后，将对过去几个世纪的记录给予一定的关注，以提高作为海冰和水文条件示踪剂的藻囊的准确性，并评估人类活动的影响，特别是在受富营养化影响的河口和沿海地区。将使用的沉积记录包括在北大西洋综合大洋钻探计划国际考察（2004年）、北冰洋HOTRAX考察（2005年）和国际极地年“WarmPast”项目中在北极和大西洋之间的主要海床弗拉姆海峡收集的岩心。这项研究是通过合作进行的，以确定年表，重建气候和海洋参数，以及气候-海洋模型评估。从方法论的角度来看，我的贡献主要是关于dinocysts和他们的使用作为示踪剂的海面条件（海冰，温度，盐度，生产力）。

The present program has two major components. One addresses a critical element of the climate-ocean system: the linkage between the Arctic and North Atlantic oceans and its impact on large-scale oceanic circulation changes. The other is methodological and concerns the use of fossil algae (dinoflagellate cysts = dinocysts) from marine sediments to reconstruct changes in hydrographic conditions at high latitudes. The ultimate goal of the research is to produce the best possible reconstructions of past climate and ocean synopses during the last two million years, with special attention paid to warm episodes, to support predictive climate-ocean modeling efforts. Long sedimentary records will thus be examined to identify intervals that have been free of perennial Arctic sea-ice and evaluate the impact of reduced sea-ice and Greenland ice volume on the climate and oceanic circulation in the NW North Atlantic. Detailed analyses of sediment cores spanning the present interglacial (the last 11,000 yrs) will be made to examine natural variability of the Arctic sea-ice and NW North Atlantic hydrography, and to explore the millennial pacing and linkages between Arctic sea-ice production and freshwater-meltwater export into the North Atlantic. Finally, some attention will be given to records spanning the last centuries in order to improve the accuracy of dinocysts as tracers of sea-ice and hydrographic conditions and to evaluate the impact of human activities, particularly in estuarine and coastal areas that are affected by eutrophication. Sedimentary records to be used include cores collected during the international expeditions of the Integrated Ocean Drilling Program (IODP) in the North Atlantic (2004), the HOTRAX expedition in the Arctic Ocean (2005), and the International Polar Year "WarmPast" project in Fram Strait, which is the main sill between the Arctic and Atlantic oceans. This research is conducted through collaboration for the setting of chronologies, the reconstruction of climate and ocean parameters, and climate-ocean model assessment. From a methodological point of view, my contribution mostly concerns dinocysts and their use as tracers of sea-surface conditions (sea-ice, temperature, salinity, productivity).