Here, we analyzed each CTD cast where nitrate or phosphate was measured. Nitrate profiles inclusive of nitrite concentrations (i.e., nitrate + nitrite) were excluded from our analysis, as were any negative or outlier concentrations. We defined outlier concentrations as instances where a nutrient decreased with depth by more than 10 µmol kg -1 in the upper ocean. Nutrient concentrations were predominantly in units of μmol kg -1 , but for concentrations expressed as μmol L -1 , we converted them to μmol kg -1 by calculating seawater density. We calculated density using a UNESCO formula by incorporating temperature (℃) and salinity (psu) measurements included in each bottle file (57).