| Summary: | Maintenance and Update Frequency: irregular Statement: Common methodologies: Blubber analysis of southern elephant seals The biopsy site was located by measuring 5–7 cm laterally from a site on the posterior dorsal surface of the seal (Best et al. 2003). A 2 cm x 2 cm square area was shaved and disinfected with an alcohol swab. A 1 cm anterior–posterior line was cut through the skin, and the biopsy corer (6 mm in diameter) was inserted into this incision. Biopsies contained ‘whole’ cores of blubber from the skin to the muscle layer. No suturing of the incision was required. Each core was placed into a vial containing a solvent mixture of 2 : 1 v/v chloroform and methanol, and 0.05% by weight of the anti-oxidizing agent, butylated hydroxytoluene. Samples were maintained at 220 °C until lipid analysis. Lipids were extracted following Best et al. (2003). Briefly, we used a modified version of the Bligh & Dyer (1959) one-phase methanol–chloroform–water extraction (ratio modified to 2 : 1 : 0.8 by volume). Chloroform and saline water were added to separate the phases following overnight extraction (final solvent ratio of 1 : 1 : 0.9 by volume). Solvents were removed using rotary evaporation (40 °C), and the total lipid (TL) extracted (greater than 98%) was dissolved in chloroform and an aliquot treated with methanol–hydrochloric acid–chloroform (10 : 1 : 1 v/v/v; 80 °C; 2 h). TL samples were vortexed two to four times during that time to maximize conversion to FA methyl esters (FAME). The FAME were extracted three times into hexane–chloroform (4 : 1 v/v, 3 ml ´ 1.8 ml; 11 ml water) and subjected to gas chromatographic analyses using a Hewlett Packard 5890A GC (Avondale, PA, USA). Peaks were quantified with Waters Millennium software (Milford, MA, USA). Individual components were identified by comparing retention-time data with authentic and laboratory standards. Integrated chromatograms were normalized by expressing the FA components as percentages of the total FA. FA components that occurred at less than 0.5% ...
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