Development of lipids during a spring plankton bloom in the northern North Sea: II. Dissolved lipids and fatty acids

During the spring plankton bloom (1976) in the northern North Sea the fatty acid and lipid distribution of the chloroform extractable fraction of seawater was analyzed by gas chromatography and thin-layer chromatography. The fatty acids in the seawater made up about 3% of the total dissolved organic matter. Maximum concentrations during the first phytoplankton bloom were in the range of 5 μmol C dm^?3. Palmitic acid (30.4%) and oleic acid (21.4%) as well as myristic, stearic and palmitoleic acids were the main fatty acids. The concentrations of fatty acids were higher below the thermocline in the deeper layers of the water column. The oleic acid showed large fluctuations, especially below the thermocline and seemed to be bound in a polar fraction. Different lipid classes containing fatty acids were determined by thin-layer chromatography. An estimation showed that the free fatty acid fraction made up the main portion (47.9%), followed by the triacylglycerol fraction (22.8%) and a more polar fraction with 25.1%. The triacylglycerol fraction appears to be more stable than the other fraction in the water column.