Dissolved nutrient and particulate material concentrations and phytoplankton abundance and community composition from cruise JC211 to South Georgia, Southern Ocean, February 2021

Marine macronutrient and particulate material concentrations together with phytoplankton abundance and community composition were measured from samples taken during British Antarctic Survey and UK National Oceanography Centre research cruise JC211 to the Scotia Sea, Southern Ocean, carried out onboard RRS James Cook in February-March 2021. Samples were taken from four sections of the cruise: (i) at the British Antarctic Survey Scotia Sea Open-Ocean Observatory (SCOOBIES) P3 mooring in the Georgia Basin, northwest of South Georgia; (ii) as part of the British Antarctic Survey long-term Polar Ocean Ecosystem Time Series - Western Core Box (POETS-WCB) survey at South Georgia; (iii) in the vicinity of giant iceberg A-68A and associated icebergs; and (iv) as part of the A23 repeat hydrographic section. Samples were collected to maximum depth of approximately 500 m from Niskin water bottles attached to a CTD rosette. Full data analyses were performed post-cruise. Concurrent temperature, salinity, dissolved oxygen, chlorophyll fluorescence and photosynthetically active radiation (PAR) measurements obtained from analysis of water samples and from sensors on the CTD system at the depth and time of each water sample are provided for environmental context. RRS James Cook cruise JC211 was in part supported by the Natural Environment Research Council (NERC) National Capability Science (Antarctic Logistics and Infrastructure; NC-ALI) programme. Further funding for sampling around iceberg A-68 was provided by the Government of South Georgia and the South Sandwich Islands and the UK Government Blue Belt Programme. Data acquisition and analyses were supported by NERC NC-ALI funding to the Ecosystems CONSEC Programme and NERC Grants NE/N018095/1 (ORCHESTRA) and NE/V013254/1 (ENCORE) at the British Antarctic Survey, and by the European Research Council (ERC Starting Grant 678371 ICY-LAB to K Hendry) and NERC Grant NE/K010034/1 (to SF Henley).