| Summary: | Sea ice is an important component of Earth’s climate system; it plays major roles in albedo, carbon dioxide exchange, ocean circulation, and is an integral component of polar ecosystems. Sea ice in the Arctic, however, is rapidly declining; a decline which is projected to maintain throughout the 21st century as the annual mean global surface temperature rises. The possibility of a nearly ice-free Arctic Ocean will have negative consequences for the Earth’s climate system, such as creating positive feedbacks that will intensify warming. Reconstructing the past observational (satellite-based) records since 1979 of Arctic sea ice and sea surface conditions provides essential context for the recently observed multi-year sea ice decline. The primary objective of this project is to analyse biomarker (IP25 and brassicasterol/dinosterol) content in surface sediments of the Canadian Arctic Archipelago. This calibration will then be used as a basis on which to reconstruct sea-ice histories over the historical past from longer marine sediment cores. By recovering IP25 and phytoplankton biomarker concentrations from marine sediment cores, PIP25 sea ice indices for the Northwest Passage can be calculated. This sea ice index can be used to reconstruct specific past sea ice conditions, such as first-year vs multi-year ice cover, in a specific region. Subsequently, these results can be mapped. In order to compare current sea-ice with the historical past, current PIP25 values need to be related to observed modern sea ice conditions, therefore providing a regionally appropriate calibration for the study of past conditions in the geological record. Discipline: Earth and Planetary Sciences Faculty Mentor: Dr. Anna Pienkowski
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