Characterizing Southeast Greenland fjord surface ice and freshwater flux to support biological applications

Abstract. Southeast Greenland (SEG) is characterized by complex morphology and environmental processes that create dynamic habitats for resident marine top predators. Active glaciers producing solid ice discharge, freshwater flux, offshore sea ice transport, and seasonal landfast ice formation all contribute to a variable, transient environment within SEG fjord systems. Here, we investigate a selection of physical processes in SEG to provide a regional characterization to reveal physical system processes and support biological research. SEG fjords exhibit high fjord-to-fjord variability regarding bathymetry, size, shape, and glacial setting, influencing some processes more than others. For example, the timing of offshore sea ice formation in fall near SEG fjords progresses temporally southward across latitudes while the timing of offshore sea ice disappearance is less dependent on latitude. Rates of annual freshwater flux into fjords, in contrast, are highly variable across SEG, with annual average input values ranging from ~1x108 m3 to ~1.25x1010 m3 (~0.1–12.5 Gt) for individual fjords. Similarly, rates of solid ice discharge in SEG fjords vary widely – in part due to the irregular distribution of active glaciers across the study area (60° N–70° N). Landfast sea ice, assessed for 8 focus fjords, is seasonal and has a spatial distribution highly dependent on individual fjord topography. Conversely, glacial ice is deposited into fjord systems year-round, with the spatial distribution of glacier-derived ice dependent on glacier termini location. As climate change continues to affect SEG, the evolution of these metrics will be individually variable in their response, and next steps should include moving from characterization to system projection. Due to projected regional ice sheet persistence that will continue to feed glacial ice into fjords, it is possible that SEG could remain a long-term (century to millennia scale) refugia location for polar bears and other ice-dependent species, demonstrating a need for continued research on the SEG physical environment.