The International Polar Year (IPY) Circumpolar Flaw Lead (CFL) System Study

The Circumpolar Flaw Lead (CFL) system study supported a large multidisciplinary overwintering in the Banks Island (NT) flaw lead over the period September 2007 to August 2008 as part of the International Polar Year (IPY). The CFL system is formed when the central pack ice (which is mobile) moves away from coastal fast ice, opening a flaw lead. The CFL forms in the fall and continues as thin ice or open water throughout the winter. The flaw lead is circumpolar, with recurrent and interconnected polynyas occurring throughout the Arctic. The overarching objectives of the CFL project were to contrast the physical and biological systems of the flaw lead open water and thin ice to the adjacent landfast ice cover. The Canadian Research Icebreaker (NGCC Amundsen) completed the first-ever overwintering of a research icebreaker in the flaw lead while staying mobile throughout the year. She supported a total of 11,000 person days distributed across 350 investigators from 27 different countries. The project obtained many first-ever measurements of a complete suite of physical, biogeochemical, contaminant and marine ecosystem variables. In this paper we present an overview of the early results from this study with a particular focus on the role of sea ice edges (both fast and marginal) in modifying the physical, biological and geochemical processes that occur across this interface. Inuvialuit traditional knowledge of these ice edges illustrates a rich physical and ecological environment. Western science results show the temporal nature of edges and the associated stimulation of biological productivity make these a particularly important part of the flaw lead system.