Subtropical Gyre Nutrient Cycling in the Upper Ocean: Insights From a Nutrient‐Ratio Budget Method

We use a nutrient-ratio budget method to investigate the relative importance of different nutrient source and sink terms at time-series Station ALOHA Bermuda Atlantic Time-series Study (BATS) in North Pacific subtropical gyres, respectively. At mean state conditions over annual multi-year time scales, vertical phosphate () supply from subsurface accounts for ∼60% total phosphorus both sites. Dissolved organic matter transport zooplankton excretion are more important phosphorous export pathways than sinking particles BATS. The approach provides quantitative, observation-based constraints on sources sinks surface ocean, which helps improve our understanding biological carbon pump oligotrophic oceans.