Dataset: Stoichiometric traits and environmental parameters from surface samples collected on GOSHIP expedition I08S in the Southern Indian Ocean from February 21 to April 1, 2024

At each of the 66 stations, we sampled surface water (~5 meters (m)) using a (SIO) STS 36-place yellow rosette sampler. We prepared samples for single-cell trait analyses in clean conditions by resting 3 to 5 drops (~10 microliters (µL)) of seawater on SF200 Ni grids (Cat: SF200-NI, Electron Microscopy Sciences) using a micropipette. The grids were air-dried for approximately 50 seconds between each drop of seawater. We removed the excess water using a tapered rolled corner of fresh Kimwipe, to avoid excess accumulation of salt particles on the grid. The process was repeated 3 to 5 times for each grid. In total, 6 to 10 grids were prepared for the surface water samples at each station. The samples were analyzed onshore in the Analytical Research Core's (ARC) electron microscope facility at Colorado State University, Fort Collins. We measured the dissolved nutrients, including ammonium, nitrite, nitrate, phosphate, and silicate onboard using a Seal Analytical continuous-flow AutoAnalyzer 3. Temperature, salinity, and fluorescence (chlorophyll) data were obtained from the sensors mounted on the CTD rosette sampler.