On the use of lipid biomarkers in marine food web analyses: An experimental case study on the Antarctic krill, Euphausia superba
Limnol. Oceanogr., 48(4), 2003, 1685-1700 | DOI: 10.4319/lo.2003.48.4.1685
ABSTRACT: The application of marker fatty acids to trace the feeding habits of Euphausia superba (krill) has produced contradictory results. We examined the effects of various diets on the fatty acid composition of larval, juvenile, and adult E. superba collected in April 1999 in the southwest Lazarev Sea and in April 2001 in the Bellingshausen Sea. Specimens were fed four different diets (mixed phytoplankton, mixed ice algae, the ice diatom Fragilariopsis cylindrus, and mixed copepod assemblages) or starved for up to 44 d. Total lipid content, lipid classes, and fatty acid composition showed very little variation in juvenile and adult krill with the different feeding regimes. Furcilia lipids were much more strongly influenced by the fatty acid signatures of their food. No stage-specific food preferences were detected in the larvae, and spatial patterns were mirrored by all furcilia stages. Comparison of the fatty acid profiles of the offered food with those of the subsequently excreted feces indicated preferential assimilation of polyunsaturated fatty acids by E. superba .