Nitrite Cycling in Warming Arctic and Subarctic Waters

The primary nitrite (NO2?) maximum (PNM) is a typical feature of oceanic nitrogen (N) cycle, yet its characterization in the world ocean remains gap. By combining natural abundance NO2? isotopes with geochemical model, we report for first time that formation Arctic and subarctic PNMs dominated by ammonia oxidation, while oxidation main sink. Notably, plays more important role waters than low- mid-latitude waters. residence PNM further suggests cycle Ocean dynamic other marine ecosystems. Our findings provide insights into N dynamics upper ecosystem.