Non-photochemical relaxation experiments were conducted by introducing seawater samples (~3mL) to a Fast Repetition Rate fluorometer (FRRF; Soliense Inc.) optical cuvette. Samples came either from underway seawater lines onboard oceanographic vessels, or were subsampled from niskin bottles during on-station sampling. Samples were exposed to a relatively high irradiance level, 500 umol photons m^(-2) s^(-1) for one minute and then were continuously monitored for 30 minutes under low irradiance condition (5 umol photons m^(-2) s^(-1)). Actinic light was provided by LED lamps within the FRRF controlled by Soliense software. Non-photochemical quenching yields recorded through the observation period were fit with a three-component exponential decay model to characterize the relaxation rates of individual quenching components. Both the raw data and fitted parameters are available here. The dataset is divided by sampling region (Canadian Arctic underway data, Canadian Arctic on-station data, Svalbard Archipelago data). See Sezginer et al. (2023) for further details regarding the treatment of samples and computational analysis of fluorescence data.
