Estimates of mixed lyer gross primary productivity and photophysiology based on underway Lagrangian measurements of the dissolved chlorophyll fluorescence of phytoplankton usung Fast Repetition Rate Fluorometry (FRRF)

GPP was estimated on the P1706 cruise based on the photo-physiology of the mixed-layer phytoplankton community measured by FRRF. Shipboard measurements were made using a bench-top FastAct 2+ Fast TRAKA instrument (Chelsea, UK) plumbed into the ship’s running seawater system. Photosynthesis versus irradiance (P vs. E) curves were run continuously on a ~45 min sampling interval.