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

该研究项目的目的是提供关于拉布拉多海岸和巴芬湾关键复冰区（即被海冰包围的开放水域）海冰长期演变、初级生产和水文参数的详细定性和定量信息。一系列的微化石和地球化学分析将对跨越全新世中期到晚期（0-8000年）的海洋沉积物岩心进行，在此期间发生了几次冷暖气候间隔的转变。特别是，该项目预计将由两名硕士研究生和两名博士研究生对硅藻和鞭毛藻囊组合和地球化学示踪剂进行广泛的分析，并辅以我自己的下核硅藻分析。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quimubec大学的同事密切合作进行。

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.