| Summary: | Two long-term mooring systems with two cone-shaped multi-sampling traps (FEVI10 and FEVI13; 2005-2007; SMT 230 K.U.M.; sampling area 0.5m2) was deployed in the HAUSGARTEN area at 79°01.00N, 04°20,62E (FEVI10) and 79°00,82N, 04° 20.5E (FEVI13). The highly branched isoprenoid IP25 as indicator for sea-ice distribution, the sterols campe- and sitosterol as proxies for terrestrial input, and the diatom-specific fatty acids (C16:1, C20:5) as well as the dinoflagellate-specific fatty acids (18:4, 22:6) were analysed by gas chromatography (GC) and/or gas chromatography-mass spectrometry (GC-MS). Biomarker analyses of campesterol (24-methylcholest-5-en-3β-ol), sitosterol (24-ethylcholest-5-en-3β-ol), fatty acids and IP25 were extracted with dichlormethane/methanol (1:1, v/v) and dichlormethane using separating funnels. For quantification of the lipid compounds, the internal standards 7-hexylnonadecane, C36 n-alkane, 19:0 FAME, and androstanol (5α-androstan-3β-ol, 20 μl/sample) were added prior to further analytical steps. The different compounds (IP25 and sterols) were separated via open column chromatography (SiO2) using n-hexane (for the hydrocarbons) and ethyl acetate/n-hexane (20:80 v/v for sterols) as eluent. The individual sterols were silylated with 500 μl BSTFA (bis-trimethylsilyl-trifluoroacet-amide) at 60°C for 2 h. After extraction with hexane, analyses were carried out. IP25 was quantified using its molecular ion m/z 350 in relation to the abundant fragment ion m/z 266 of 7-hexylnonadecane and by means of an external calibration curve (R2 = 0.9989) to balance the different responses of the used ions. Campesterol and sitosterol were quantified as trimethylsilyl ethers using the molecular ions m/z 472, and m/z 486, respectively, in relation to the molecular ion m/z 348 of androstanol. The fatty acids were qualified using an external standard mixture and quantified by 19:0 FAME.
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