Sea-ice and polynya productivity in relation to climate-induced environmental changes along the Baffin and Labrador Currents during the Holocene

这项研究计划的目的是提供详细的定性和定量资料，说明位于拉布拉多海岸和巴芬湾的关键经常性波尼亚(即被海冰包围的开阔水域)海冰的长期演变、初级生产力和水文参数。将对全新世中晚期(0-8000年)的海洋沉积岩心进行一系列微化石和地球化学分析，在此期间发生了几次气候变冷和变暖的过渡。特别是，该项目预计将由两名硕士学生和两名博士生对硅藻和甲藻包囊组合和地球化学示踪剂进行广泛的分析，并辅之以我自己的下岩心硅藻分析。这项工作将与加拿大地质调查局、丹麦和格陵兰地质调查局以及魁北克大学的同事密切合作。海洋初级生产者--以蓝藻、硅藻和甲藻等海洋食物网为基础的光合作用生物--在生态系统的生物化学和功能中发挥着关键作用。它们的生态受海洋的物理和化学性质(如海面温度和盐度、海冰覆盖、海洋环流等)的支配，使初级生产者对气候变化高度敏感，并指示气候变化。为了对当前和未来北极变暖对巴芬/拉布拉多沿海水域及其反复出现的多尼阿水域的生产能力和后果作出可靠的预测，需要完全了解该系统对气候波动的反应。通过研究过去对气候变化的可比系统响应，可以获得这样的理解。拟议的方案将有助于理解多尼雅对北极生产力预算的贡献及其作为碳汇的作用。研究活动将有助于在古环境研究的不同阶段培养高素质的人才。将产生的数据将提高我们衡量当前和未来气候变化对这些波利尼亚地区历史上一直保持的生态系统服务的影响的能力，并将帮助当地北方社区预测和准备这些变化的潜在经济和社会后果。最后，拟议的项目符合正在进行的更好地了解气候系统和验证区域气候模型的更大框架，在区域气候模型中，海冰和初级生产力构成关键组成部分。

The objective of this research program is to provide detailed qualitative and quantitative information on the long-term evolution of sea ice, primary production and hydrographic parameters in key recurrent polynyas (i.e. areas of open-water surrounded by sea-ice) located along the Labrador coast and in Baffin Bay. A series of microfossil and geochemical analyses will be performed on well-dated marine sediment cores spanning the middle to late Holocene (0-8000 years), during which several transitions between colder and warmer climate intervals have occurred. In particular, the program foresees extensive analysis of diatom and dinoflagellate cyst assemblages and geochemical tracers by two MSc students and two PhD students, complemented by my own downcore diatom analysis. This will be done in close collaboration with colleagues from the Geological Survey of Canada, the Geological Survey of Denmark and Greenland, and Université du Québec.Marine primary producers - photosynthetic organisms at the basis of marine food webs such as cyanobacteria, diatoms and dinoflagellates - play a crucial role in the biochemistry and functioning of ecosystems. Their ecology is governed by the ocean's physical and chemical properties (e.g. sea-surface temperature and salinity, sea ice cover, ocean circulation, etc.), making primary producers highly sensitive to, and indicative of, climatic changes. In order to make reliable predictions about the magnitude and consequences of current and future Arctic warming on the productive capacity of the Baffin/Labrador coastal waters and their recurrent polynyas, a complete understanding of the response of the system to climate fluctuations is required. Such an understanding can be obtained through the study of comparable system responses to climatic changes in the past.The proposed program will help to understand the contribution of polynyas to the Arctic productivity budget and their role as carbon sinks. The research activities will contribute to the training of highly-qualified-personnel along different steps of paleo-environmental studies. The data that will be produced will increase our capacity to gauge the impact of present and future climate changes on the ecosystem services that these polynyas have historically maintained and will help local northern communities to anticipate and prepare for the potential economic and social consequences of these changes. Finally, the proposed project fits within the larger framework of ongoing efforts to better understand the climate system, and validate regional climate models in which sea ice and primary production constitute key components.