Physical-chemical dataset during the West Wind Drift Cruise during spring 2018

The WWD bifurcation was investigated during a spring 2018 cruise aboard the R/V Cabo de Hornos, covering 29 stations across the northern and southern WWD, Moraleda Channel, and Gulf of Penas. Water was collected using a CTD-rosette system for analyses of coccolithophores, Chl-a, nutrients, and carbonate chemistry. For coccolithophore identification and quantification, duplicate 200–300 mL samples were filtered onto 0.8 µm polycarbonate filters. Portions of the dried filters were gold-coated and examined with SEM (20,000–25,000×) to identify species and G. huxleyi morphotypes. Total coccolithophore abundances were determined by cross-polarized light microscopy counts of 20 fields per filter, and species/morphotype abundances were calculated by combining SEM-derived relative abundances with total counts.