Figure 4b: 500 MHz 13C NMR part spectra representing different chemical shift regions of algal oils of Tetraselmis aff chuii (TSG4F2SPSE), Chlorella vulgaris (CHLWCSPSE) and Spirulina platensis (SPRM6E). Regions: 10-45 ppm = long alkyl chain, 170-174 ppm = carbonyl regions. Signals marked 15 = C22:6; 16=C20:5; 17 = C18:3.