Base de données de recherche des TNO

étiquettes: physical sciences, hydrology, glaciology, sedimentology, paleoclimatology, bathymetry, paleontology, oceanography, geophysics

Objectif(s): To investigate the origin of the Younger Dryas cooling that began about 13,000 years ago.

Description du projet: Here is the project summary from the (U.S.) National Science Foundation proposal that led to this expedition: The research team propose a three-year project to investigate the origin of the Younger Dryas cooling that began about 13,000 years ago. For decades this cold event has been associated with sea ice in the Arctic and North Atlantic Oceans, and the storage and release of fresh water from a large glacial lake in North America, yet its origin remains controversial. New evidence suggests that the glacial lake (Lake Agassiz) released fresh water to the Arctic through the Mackenzie River and the research team propose that this signal should be detectable along the western margin of the Canadian Archipelago in the oxygen isotope ratio in the shells of planktonic foraminifera. The project begins with a three-week expedition to survey the seafloor and sub-bottom layers and collect sediment cores from the eastern Beaufort Sea, a region that is remote and has not been well explored. The Intellectual Merit of this project stems from its interdisciplinary nature and the global climate implications of the expected results. Besides the sediment processing and micropaleontology that are part of generating the isotope data that reflect sea surface salinity, there will be two complementary shore-based projects. The first is to integrate the new geophysical data on the continental margin with the climate history of the open sea, sediment transport, relative sea level change, and terrestrial climate, as it has been done previously for the Chukchi Sea. The second is to compare the geochemical data with results from a high resolution General Circulation Model that is configured to reveal the path and the mixing of the melt water. Although the paleoceanographic data will be spatially limited, model runs will show the low salinity distribution in the Arctic as well as in the Nordic seas where the freshening may have affected deep ocean overturning and caused the Younger Dryas cooling. The Broader Impacts of this project are several. Each Principal Investigator has a serious commitment to education and public outreach. This project will support three graduate students who will be vested in all aspects, beginning with the research cruise. At least one undergraduate science major will sail with the research team as well. Each PI has been involved with local primary and secondary schools, either by making presentations, hiring students for the summer, mentoring science fair projects, and contributing to curriculum development. Finally, funds are requested to support the participation of a high school physics teacher on the cruise. The research team will have room for observers but it may be a logistical challenge to get someone onboard as the research team will be departing and arriving at Barrow, Alaska. The work will be educational and interacting with the crew and scientists will be good for all parties. The best way will be to have someone such as a teacher or community leader participate. In the principal researchers experience it will take 2-3 years to know if the project is successful and maybe another year until the first publication. The research team can arrange to have copies of the work sent to local communities, or can post results on the web for easier access. Also, the research team are hoping someone from the scientific party will blog about the cruise as the three week journey progresses. The fieldwork for this study will be conducted from August 18, 2013 to September 7, 2013.