Seasonal Relationship Between Net Primary and Net Community Production in the Subtropical Gyres: Insights From Satellite and Argo Profiling Float Measurements

Abstract

AbstractThe ratio between net community production (NCP) and net primary production (NPP) is a useful index of carbon export efficiency (e‐ratio). Seasonal variations of e‐ratio are poorly documented due to the lack of field measurements. In this study, the satellite‐based NPP and Argo‐Oxygen (O2) based NCP were used to determine e‐ratio in the subtropical gyres. Comparisons with long‐term field measurements at the Hawaii Ocean Time‐Series showed good agreement in annual mean and spring‐summer (April–July) e‐ratio. With the short‐term tracer (O2) the satellite‐Argo approach revealed significant seasonal variations in NCP and e‐ratio in the subtropical gyres of the North Pacific, North Atlantic, and South Pacific. The satellite‐Argo‐derived annual mean e‐ratio in all three Northern Hemisphere sites were close to those from the temperature‐based empirical model, but significantly lower in the South Pacific subtropical gyre where the sub‐annual NCP variations were stronger.