Fig. 3: Lipid group concentrations in the identified clusters.

Average concentration of total intact polar lipids (a), chloroplast lipids (b), cell membrane lipids (c), archaeal lipids (d), total quinones (e), photosynthetic quinones (f), ubiquinones (g), menaquinones (h), total pigments (i), chloropigments (j), carotenoid pigments (k), and triacylglycerols (l) in the five sub-clusters of sampling stations identified by the hierarchical clustering analysis of surface mixed-layer samples collected during M156 off Mauritania. Boxes represent the interquartile ranges, the line within the box the median, and the whiskers extend to the minimum and maximum values within 1.5 times the interquartile range. Outliers are shown as circles. Asterisks indicate variables significantly different (one-way ANOVA, p < 0.05) from coastal (dark blue) and open-ocean (light blue) stations, respectively. The chloroplast lipids are the sum of glycolipids with diacylglycerol side chain, including the galactolipids mono- and digalactosyldiacylglycerol and the sulfolipid sulfoquinovosyldiacylglycerol. The cell membrane lipids include all phospho- and betaine lipids. The archaeal lipids contain all core and intact polar diether and tetraether lipids. The respiratory quinones are separated into photosynthetic quinones (plastoquinone and vitamin K1), ubiquinones and menaquinones. The pigments are divided into chloropigments, which is the sum of chlorophylls and related compounds (porphyrin ring-containing molecules) and carotenoid pigments, which include all xanthophylls (e.g., fucoxanthin and zeaxanthin) and β-carotene. For an overview of the chemical structures, the reader is referred to Supplementary Fig. 4.