N-alkane composition of marine and terrestrial sedimentary archives from sub-Antarctic South Georgia

• Main Authors: Berg, Sonja, Kusch, Stephanie, Jivcov, Sandra
• Format: Dataset
• Language: English
• Published: PANGAEA 2024
• Subjects: (C23+C25)/(C23+C25+C29+C31) n-alkanes ratio; ANT-XXIX/4; Area/locality; Calculation according to Ficken et al. (2000); Calculation according to Marzi et al. (1993); Calculation according to Poynter & Eglinton (1990); Carbon Preference Index; n-Alkanes; Co1305; Co1306; Co1308; Comment; Cruise/expedition; DATE/TIME; Depth; bathymetric; bottom/max; sediment/rock; top/min; DW-SG_062; DW-SG_063; DW-SG_064; ELEVATION; Event label; Fjord; Gas chromatography - Flame Ionization Detection (GC-FID); GC; Gravity corer; lake; LATITUDE; LONGITUDE; n-Alkane; average chain length; n-Alkane C21 of total alkanes; n-Alkane C22 of total alkanes; n-Alkane C23 of total alkanes; n-Alkane C24 of total alkanes; n-Alkane C25 of total alkanes; n-Alkane C26 of total alkanes; n-Alkane C27 of total alkanes; n-Alkane C28 of total alkanes; n-Alkane C29 of total alkanes; n-Alkane C30 of total alkanes; n-Alkane C31 of total alkanes; n-Alkane C32 of total alkanes; n-Alkane C33 of total alkanes; n-Alkane C34 of total alkanes; Antarc*; Antarctic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.967405; https://doi.org/10.1594/PANGAEA.967405

The dataset comprises N-alkane composition data that was obtained on sediment samples from sub-Antarctic South Georgia. The sediments were collected from a range of different sites, including lakes, peat deposits, a marine inlet and a fjord during RV Polarstern expedition PS81 in 2013. Prior to the geochemical analyses reported here, the sediments were freeze-dried and ground. More details on the study sites, sampling and data evaluation can be found in Berg et al. (submitted manuscript). Alkyl lipid biomarkers were extracted by accelerated solvent extraction (ASE 300, Thermo, USA) with dichloromethane and methanol (DCM, MeOH; 9:1, v/v at 120°C, 75 bar) (cores Co1305, PS81/283, and Co1308) or via consecutive ultrasonication in DCM:Hexan (1:1), MeOH:DCM (1:1) and MeOH (core Co1306 and the peat and soil samples). The total lipid extract (TLE) was saponified with 0.5 M KOH in MeOH and water (9:1, v/v) at 80°C for 2 h. Neutral lipids (NL) were extracted from the TLE with dichloromethane by liquid-liquid phase separation. Alkanes were purified from NL by silica gel column chromatography (SiO2, deactivated, mesh-size 60) by elution with hexane. Analysis was conducted by gas chromatography (GC, Agilent 7890B, Agilent Technologies, USA) equipped with a flame ionization detector (FID). Alkanes were identified and quantified against authentic external standards. Concentrations are given as fractional abundances for the compound class.