Vulnerability of the Arctic Marginal Ice Zone to Changes in Drifting Ice

The marginal ice zone (MIZ) is one of the most important and dynamic features in the Arctic. The PIs will conduct an integrated analysis of how delivery of sea ice to the MIZ changed in the past and what changes might be in store in the future. Using a sea ice dynamic model forced with contemporaneous atmospheric fields and including tracers, they will track the origin and transport pathways of sea ice, and the focused release of material from ice melting in the MIZ. They will then extend this analysis back into the past, to examine changes during the Holocene, and into the future, using the Intergovernmental Panel on Climate Change climate change scenarios. They will investigate mixing of ice from different source areas into the Arctic interior; and assess how interannual and seasonal variability in ice from different source regions has influenced, and may influence in the future, redistribution and delivery of freshwater, sediments and biological material. Intellectual Merit This research integrates models with existing data into a new framework, that of an ice conveyor which transports material across the Arctic basin and releases it in the environmentally sensitive MIZ. Through this project the PIs will examine: . How has the distribution, origin, and age of ice delivered to various MIZ regions changed over time, and during critical seasons, i.e. the spring bloom? . How have changes in ice drift influenced the delivery of freshwater, sediments, and biological material? How are these changes related to observed changes in atmospheric, oceanic, sedimentologic, and ecologic conditions? . How have changes varied regionally and with respect to water depth? For example, when does maximum ice melt - and therefore material release - occur over deep waters of central Fram Strait vs. over the shallow Greenland Shelf in western Fram Strait? . What changes in the distribution, origin, age, and MIZ flux of ice might we expect in the future? What might be the impact of these changes?