This data set shows winter phytoplankton distribution and trace metal data parallel sampled from the upper 150 m of the Indian sector of the Southern Ocean along the 30°E longitude during the Winter 2017 Cruise onboard the SA Agulhas II. The data set contains phytoplankton pigment concentrations (HPLC), phytoplankton community composition (group chla concentration and percentage via CHEMTAX), macronutrient concentrations, and dissolved and particulate trace metal concentrations. The data set also contains various other parameters (Turner Fluorometer Chla and POC) that were previously published in Weir et al. (2020) for this cruise and relevant to this study. Also contained is a file for all the trace metal data (dissolved and particulate) in the upper 250m of the transect and associated trace metal star (Metal*) values calculated according to Moore (2016) - http://dx.doi.org/10.1098/rsta.2015.0290. This data is related to the publication by Viljoen et al. titled: Winter dynamics of phytoplankton and micronutrients in the Southern Ocean in JGR Oceans - https://doi.org/10.1029/2025JC022431. Original HPLC phytoplankton pigment concentration data and their limits of detection is availble in a separate repository at: https://doi.org/10.5281/zenodo.14610498.

The work leading to these results received funding from the National Research Foundation (NRF), South Africa, under the South African National Antarctic Programme (SANAP), grant numbers 93072, 110731, and SANCOP, grant number 91313, awarded to S. Fietz. J.J. Viljoen acknowledges funding from NRF through a Masters Innovation Scholarship and financial assistance through a PhD NRF grant-linked bursary through the South African National Antarctic Programme, grant number 110731. We extend our gratitude to Shantelle Smith, Raquel Flynn, Raymond Roman, Kurt Spence, and Sarah Fawcett (University of Cape Town) for providing the macronutrient data from the Winter 2017 voyage. We also acknowledge and thank David Walker (CPUT) for use of fluorometer chlorophyll-a data. We thank Captain Knowledge Bengu and the crew of the SA Agulhas II for their support. We furthermore thank chief scientist Marcello Vichi, UCT-Oceanography, and all the cruise participants of the Winter 2017 scientific voyage.