Coastal marine systems are active regions for the production and emission of nitrous oxide (N 2 O), a potent greenhouse gas. Due to the inherently high variability in different coastal biogeochemical cycles, the factors and mechanisms regulating coastal N 2 O cycling remain poorly understood. Hydroxylamine (NH 2 OH), a potential precursor of N 2 O, has received less attention than other compounds in the coastal areas. Here, we...