Lipids and fatty acids in plankton from the Finnish coastal waters of the Baltic sea

1. In the Finnish coastal waters phytoplanktonic diatoms dominate in early summer, changing to zooplanktonic Rotatoria in June and later to Copepoda.

2. The lipid contents in plankton varied from 0.2 to 2.5% wet weight or from 1.9 to 17.0% dry weight, respectively.

3. Triglycerides and polar lipids together dominated in phytoplankton while polar lipids alone were the major lipid in zooplankton. Exceptionally high proportions of free fatty acids existed in most samples whereas wax esters were detected only as minor components.

4. Over two thirds of the fatty acids in phytoplankton were composed of C₁₆ acids, whereas palmitic acid together with polyenoic C₂₀ and C₂₂ acids dominated in zooplankton.

5. Monoenoic C₂₀ and C₂₂ acids, often abundant in copepods, were found only in minor amounts in this study.