SS4.07 Lipids/Fatty Acids in Ecological Research
Date: Tuesday, June 11, 2002
Time: 10:15:00 AM
Location: Saanich
 
BecA, Lab. Biol. Protistes, Univ. Clermont II , Aubiere, France, Alexandre.BEC@lbp.univ-bpclermont.fr
Bardoux, G, , Lab. Biogeochimie Isotop., Univ Paris VI, Paris, France, 
Desvilettes, C, , Lab. Biol. Protistes, Aubiere, France, 
Bourdier, G, , Lab. Biol. Protistes, Aubiere, France, 
Mariotti, A, , Lab. Biogeochimie Isotop., Paris, France, 
 
STABLE CARBON ISOTOPE RATIOS OF INDIVIDUAL FATTY ACIDS EXTRACTED FROM DAPHNIA AND DIFFERENT FOOD SOURCES
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Fatty acid (FA) biomarker analysis coupled with compound specific isotope analysis seems to be a powerful tool in the study of FA trophic transfer. In order to test this new approach, we conducted a preliminary study in experimental conditions. Neonates of Daphnia longispina were fed on different cultured organisms: Cyclotella cyclopuncta, Rhodomonas minuta, Cyclidium glaucoma and on a mixed diet composed of Rhodomonas and Cyclidium. Carbon isotope ratios of the major fatty acids extracted from total lipids of food sources were determined and compared to those extracted from phospholipids (PLFA) and neutral lipids (NLFA) of the Cladoceran. Analysis revealed that Cladoceran fed on Rhodomonas have NLFA isotope ratios ranging from -36.9 to -30.4 0/00 whereas those fed on Cyclidium showed values ranging from -28.2 to -23.6 0/00. Mixed diet induced greater variations (-38.3 to -24.9 0/00). Application of this approach in natural environment will be discussed.