Palynological tracers of ocean and climate changes

目前的方案有两个主要组成部分。其中一项涉及气候-海洋系统的一个关键要素：北冰洋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。另一个是方法论，涉及利用海洋沉积物中的藻类化石(甲藻胞囊=甲藻胞囊)来重建高纬度地区水文条件的变化。这项研究的最终目标是尽可能最好地再现过去两百万年的气候和海洋概况，并特别注意暖期，以支持可预测的气候-海洋模型工作。因此，将审查长期的沉积记录，以确定常年没有北极海冰的间隔，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。将对横跨当前间冰期(过去11 000年)的沉积岩芯进行详细分析，以考察北极海冰和北大西洋西北部水文地貌的自然变异性，并探讨千年以来北极海冰生产与北大西洋淡水融水输出之间的关系。最后，将对跨越过去几个世纪的记录给予一些关注，以便提高作为海冰和水文条件示踪剂的恐龙的准确性，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海洋钻探计划(IODP)国际探险(2004年)、北冰洋HOTRAX探险(2005年)和弗拉姆海峡国际极年“WarmPast”项目期间收集的岩芯，弗拉姆海峡是北冰洋和大西洋之间的主要基床。这项研究是通过协作确定年表、重建气候和海洋参数以及评估气候-海洋模型而进行的。从方法论的角度来看，我的贡献主要涉及到海藻及其作为海面条件(海冰、温度、盐度、生产力)示踪剂的使用。

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).