Nutrient amendment bioassay bottle experiments conducted between 59S 89W and 60S and 89W on cruise DY111 (CUSTARD).

This dataset contains data from nutrient amendment bioassay experiments along 89W between 54S and 60S conducted from December 2, 2019 to January 9, 2020 on the DY111 cruise. The aim of the cruise was to examine seasonal changes in biogeochemistry in the Southern Ocean across the spring bloom. Experiments were designed to investigate the phytoplankton response to nutrient and natural dust addition. Seventeen experiments in total were conducted in a dedicated incubation container set to local sea surface temperature and day/night cycle. There were seven large-volume experiments (denoted LT), eight small-volume (ST), and two gradient experiments (GE) conducted. Surface seawater for the experiments was collected using the towed fish at approximately 5 metres depth. All experiments were subsampled at T0 and T48 hours, and several experiments extended to T144 hours. Subsamples collected directly from the towed fish and from the experiments were measured for chlorophyll fluorescence and concentration of chlorophyll, particulate organic carbon, nitrogen, biogenic silica and macronutrients.