Trace metals (e.g., manganese (Mn), iron (Fe), copper (Cu), nickel (Ni), zinc (Zn), and cadmium (Cd)) are essential micronutrients for phytoplankton in the ocean. In the Arctic Ocean, oceanic inflows, continental shelves, and rivers play a dominant role in trace metal supply. The supply of trace metals to the western Arctic is thought to be dominated by nutrient-rich Pacific waters, which enter though the Bering Strait and are modified by biological cycling on the Chukchi Shelf, and then ventilate the Canadian Basin upper halocline. Repeat, high resolution (~6 km) trace metal measurements between 2021 and 2024 show that trace metal concentrations are both highly spatially heterogeneous and correlate with water mass characteristics within the Bering Strait. While warming and freshening of northward flowing Pacific waters through the Bering Strait has been observed, as well as an increase in volume transport and nitrate supply, trace metal fluxes (e.g., Mn, Fe, Ni, Zn) also may be increasing. Flux estimates provided also reflect seasonal variability between the alternate fall and summer sampling strategy over four years. Herein, we show that trace metal supply to the Arctic from the North Pacific is tightly coupled to physical circulation and may outweigh the estimated flux leaving the Arctic to the North Atlantic.

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