Chlorophyll a and macronutrient concentrations during the icebreaker Shirase cruise of the 61st Japanese Antarctic Research Expedition

Chlorophyll a concentration is the most common indicator of phytoplankton biomass, basically regulated by physicochemical properties such as temperature, salinity, macronutrients and light intensity. As part of the monitoring programs of the Japanese Antarctic Research Expedition (JARE), water temperature, salinity, chlorophyll a concentration, and macronutrients (nitrate, nitrite, phosphate, and silicic acid) have been measured since 1965. This report presents the latest data collected during the Shirase cruise in the 2019–2020 season.