First assessments of trace metal fluxes from the Pacific to the Arctic - high resolution 2021 summer measurements show surprisingly high influence of the Alaskan Coastal Water

Trace metals (manganese, iron, nickel, copper, zinc, and cadmium) are essential micronutrients for phytoplankton and can be used as tracers of oceanic processes. The supply of trace metals to the Western Arctic was thought to be dominated by macronutrient-rich Pacific waters entering through the Bering Strait and modified by uptake and regeneration on the Chukchi Shelf. However, the first high resolution (~6km) trace metal measurements in the strait (July 2021) show large variability in trace metal concentrations across the strait and a close relationship with salinity. The previously unsampled Alaskan Coastal Water has unexpectedly high trace metal concentrations, while the macronutrient-rich Anadyr Water has surprisingly low trace metal concentrations. We make the first estimates of trace metal flux from the Pacific to the Arctic through the Bering Strait and find they are elevated despite the comparatively small volume transport and, for some metals, exceed the Arctic to Atlantic exp..., Trace metal and macronutrient samples were collected July 10-16, 2021, from the R/V Norseman II during an annual Bering Strait (BS) mooring and hydrographic cruise, which sampled the eastern Bering Strait (eBS) and the A3 line (AL) sections at 6-10km resolution. Water was collected using an air-diaphragm pump (PTFE, Wilden) with inline filtration (0.2 um, Acropak), pumping water from ~5m (“surface”) or ~25-45m depth (“bottom”), sufficient resolution to define the strait’s typically two-layer stratification (Woodgate et al., 2015). Samples were collected into acid-cleaned 250 mL low density polyethylene bottles and acidified to pH 1.8 following established protocols (Jensen et al., 2020). Additionally, filtered macronutrients (nitrate (N), phosphate (P), and silicate (Si)) samples were taken from the same depths and frozen (-20°C) immediately after collection until analysis at the University of Washington Marine Chemistry Lab in October 2021, following WOCE/JGOFS protocols (Gordon et al...., , # Data for: First assessments of trace metal fluxes from the Pacific to the Arctic - high resolution 2021 summer measurements show surprisingly high influence of the Alaskan Coastal Water

[https://doi.org/10.5061/dryad.2280gb5zv](https://doi.org/10.5061/dryad.2280gb5zv)

Oceanographic data for dissolved (filtered to <0.2um) trace metals (Mn, Fe, Cu, Ni, Zn, Cd) and macronutrients (nitrate, phosphate, silicate, ammonium) in seawater. All samples were collected in the Bering Strait (Pacific-Arctic region) between 65 and 69 degrees North on the R/V Norseman II. Sampling took place in July 2021. There are 78 samples in total. Metadata (station name, location, cast, depth, temperature, and salinity) are also included. Temperature and salinity data are derived from concurrent measurements taken with an RBR Concerto CTD.

These data are used to assess fluxes of micro and macronutrients from the Pacific to the Arctic Ocean and how that may be changing over time.

**Description of the data a...