Oceans are critical to stabilizing the world’s climate, absorbing a quarter of all carbon dioxide emissions and capturing 90 percent of the excess heat they generate. By some estimates, the ocean also accounts for up to half the annual emissions of another greenhouse gas – nitrous oxide (N2O), the third most important climate emission after carbon dioxide and methane. With the climate changing amid record high atmospheric levels of all three gases, the importance of the marine nitrogen cycle is ripe for study.