Bering Strait is the only Pacific gateway to the Arctic Ocean, playing a key role in influencing the hydrographic structure and biological productivity of the western Arctic. Here we use shipboard transects occupied across the strait from 2000-2025, together with historical water sample data and an ocean reanalysis product, to elucidate the regional circulation and investigate the northward flux of nitrate into the Chukchi Sea. We identify the existence of a third circulation branch, referred to as the Little Diomede Jet (LDJ), flowing along the western edge of the US side of the strait, adjacent to the Diomede Islands. The LDJ is surface intensified, approximately 10 km wide, and advects the coldest and saltiest water that passes through the US side of the strait. It contributes roughly 35% of the total transport through the US side during the warm months of the year and carries most of the nitrate. A backward trajectory calculation using the reanalysis product indicates that the LDJ emanates from within the high-nitrate Gulf of Anadyr and has similar hydrographic characteristics to the water on the eastern side of the Russian Channel.

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