Effect of variable nutrient supply on fatty acid composition of phytoplankton grown in an enclosed experimental ecosystem

Abstract

Outdoor experimental tanks were used to simulate phytoplankton blooms in natural seawater from the bay of Villefranche-sur-Mer (France), during March-April 1984. External temperature and light intensity were respectively monitored every 4 h and daily. Nutrient conditions were followed daily and maintained by a cycle of dilutions with fresh enriched seawater. Six different cycles of phytoplankton production were followed. They differed by the dilution rates used. Nutrient uptake. phytoplankton composition, biochemical composition and detailed lipid composition of the phytoplankton were followed throughout each growth cycle. Results showed a clear difference between the first cycle, which lasted 7 d , and subsequent ones which lasted only from 27 to 51 h In terms of species composition, the initial body of water con~prised a complex assemblage of species (flagellates, dinoflagellates, diatoms, microzooplankton) which were gradually replaced by a community of diatoms dominated by Skeletonema costatum, Nitzschia sp. and Chaetoceros sp. Total fatty acid changes reflected the progressive changes in species composition (inverse variation of C16 and C18 polyunsaturated fatty acids) and to a minor extent the nutrient regime. In terms of fatty acid composition of the different lipid classes the transition from a flagellate to a diatom population appears to b e the key factor influencing all categories in a similar way. Nutrient regime affected essentially the neutral lipid composition while changes in physiological state were reflected in the polar lipid composition (phospholipids, monogalactosyl diglycerides [MGDG], digalactosyl diglycerides). Probable light limitation during the fourth growth cycle may explain some of the changes in fatty acid composition at the MGDG level. In all cases, transient saturation-desaturation processes of the membrane lipids seems at the heart of the acclimation dynamics

Fatty acid dynamics during the spring bloom in a High Arctic fjord: importance of abiotic factors versus community changes

“…The results of these studies point to two main drivers for the dynamics in fatty acid profiles: (i) changes in species composition due to natural succession, and (ii) the physiological state of the phytoplankton determined mainly by the availability of nutrients. The importance of both has been confirmed further in mesocosm experiments (Mayzaud et al 1990;Hayakawa et al 1996).…”

On the potential application of polar and temperate marine microalgae for EPA and DHA production

“…Similarly, with respect to temperature, no consistent results were found (Thompson et al 1992;Jiang and Gao, 2004;Teoh et al 2004;Chen et al 2008). Other factors influencing PUFA content suggested are CO 2 concentration, nutrient availability, growth phase and day-night rhythm (Mayzaud et al 1990;Yonmanitchai and Ward 1991;Zhukova 2004;Meiser et al 2004;Lv et al 2010). Besides intraspecific EPA and DHA variability, it is known that EPA and DHA content shows significant differences between and within algal classes.…”

Fatty acid composition in amorphous aggregates in the northern Adriatic Sea

“…The compositions Mayzaud et al 1989) or in in situ experimental large of samples A2 and A3 were similar to Group 3, with bags (Morris et al 1985, Mayzaud et al 1990), the fatty the difference being that the C16POLY/C18POLY acid proportions were similar to those measured in lab-(0.00 to 0.04) and UNS/SAT (0.30 to 0.41) ratios oratory cultures, but with lower absolute contents. were much lower than in diatom dominated aggreApproximately the same composition was also obgates.…”