Influences on Chemical Distribution Patterns across the west Greenland Shelf: The Roles of Ocean Currents, Sea Ice Melt, and Freshwater Runoff

Abstract. The west Greenland shelf is a dynamic marine environment influenced by various physicochemical and biological processes. This study provides an overview of the main factors affecting the distribution of macronutrients, carbonate system parameters, and dissolved trace elements during late summer. Key drivers include major ocean currents, melting sea ice, and terrestrial freshwater runoff, each uniquely contributing to the cycling and spatial distribution of chemical constituents. Major ocean currents, such as the southward-moving Baffin Island Current (BIC) and the northward-moving West Greenland Current (WGC), shape the chemical composition of shelf waters by introducing water masses with distinct chemical signatures. Melting sea ice is an important source of freshwater and dissolved constituents for the marine environment. The east-to-west direction of sea ice retreat creates nutrient gradients, with low nutrient levels in highly productive shelf waters and high nutrient levels in areas with prolonged ice cover. This process also affects the carbonate system, leading to changes in pH and aragonite saturation states, which is critical for the health of marine organisms. Terrestrial freshwater runoff, particularly from the Greenland Ice Sheet (GIS), replenishes macronutrients in the photic zone, stimulating primary production and creating important CO₂ sinks. However, surface waters become more susceptible to acidification by the input of poorly buffered glacial freshwater. Understanding these key drivers is essential for forecasting future changes in the marine chemistry and biology of the west Greenland shelf, especially in the context of ongoing climate change within this high-latitude region.