The identification of organic substances associated with freshwaterCeratium hirundinellacells

Phytoplankton synthesize biomolecules through the process of photosynthesis, and the decomposition of these molecules causes odors in water. While the freshwater dinoflagellateCeratium hirundinellais well known for causing a variety of odors in water, the organic acid profile of this specimen has not been studied, and the compounds causing the odors have not been identified. Therefore, the aim of this study was to identify organic substances associated withC. hirundinella cells collected from a freshwater lake. Results reveal 131 organic substances, of which 27 are regarded as important due to their substantial quantity (> 1 mg L–1). Five fatty acids and two dicarboxylic acids are identified as the most prominent organic substances, with results showing that palmitic, succinic and oleic acids are the most important organic acids produced. Besides these, 4,7,10,13,16,19-docosahex-aenoic, myristic, sebacic and palmitoleic acids also form part of the organic substance profile ofC. hirundinella. It has become evident that high quantities of organic acids associated withC. hirundinella,may not be the sole cause of odors. It is thus proposed that organic substances, present in lower quantities, should be further investigated.