Phytoplankton physiology at Chatham Rise, east of New Zealand, measured during the SalpPOOP (TAN1810) campaign onboard the RV Tangaroa

Water samples from 7 depths spanning the euphotic zone were collected using a CTD-rosette during the five Lagrangian experimental cycles conducted during Salp Particle expOrt and Ocean Production (SalpPOOP), from October to November 2018 in the vicinity of the Chatham Rise (New Zealand). Depths varied according to experimental cycle, as it was adjusted based on photosynthetically active radiation (PAR) profiles to span the depth to 0.1% of surface irradiance. The physiology of the phytoplankton community was evaluated using the Mini-Fire fast repetition rate fluorometer (FRRF), using approximately 5ml per depth. Fv/Fm and reoxidation of Qa-, the first quinone acceptor of PSII, were evaluated using the Mini-Fire FRRF, which provided indications of phytoplankton stress most likely caused by iron-limitation following the procedure outlined in Gorbunov and Falkowski (2020 doi:10.1002/lno.11581).