Cryosphere and ocean variability in Kane Basin since the 18th century: insights from two marine multi-proxy records

Abstract

Nares Strait, a marine gateway connecting the Arctic Ocean with northern Baffin Bay, is characterised by the formation of seasonal ice bridges between Canada and Greenland that prevent the southward export of multiyear sea ice. Recent observations indicate increasing instability in sea-ice formation particularly evident in Kane Basin, which either freezes over or remains open during winter and spring, depending on ice-bridge dynamics. Kane Basin is influenced by contrasting ocean currents in its eastern and western sides, as well as by the Humboldt Glacier, Greenland's widest marine-terminating glacier. Kane Basin is a critical region due to its pronounced sensitivity to cryospheric and oceanic changes. However, its long-term environmental history, particularly in the eastern sector, remains poorly constrained prior to the satellite era. Here, we present two multi-proxy sediment core records from opposite sides of Kane Basin, spanning the 18th century to the present, that we compare with Humboldt Glacier solid ice discharge and retreat since 1965 CE. Clear spatial differences are evident across the basin in terms of sediment delivery, primary productivity, and organic matter sources. Both records also reveal temporal changes, transitioning from cold sea-surface conditions with extensive sea-ice cover during the Little Ice Age (peaking around 1900 CE), towards more open and stratified waters, accompanied by a shift towards higher primary production from approximately 1950 CE to the present.