ALBERT

Description: Between 2019 and 2022 three sediment cores HH14-897-MF-GC (2014), He519_2-3 (2018), and He560_26-2 (2020) were analyzed using biogeochemical markers to assess organic carbon dynamics and its bio-availability in the Hornsund Fjord (Svalbard) sediments. Depositional history was assessed by 210Pb+137Cs data (obtained by γ-spectrometer) building the basis for associated sedimentary age models (Bruel & Sabatier, 2020), with bulk total organic carbon concentrations (using an element analyzer) and dual C-isotopes of δ13C (obtained by isotope ration mass spectrometer) and F14C (by accelerator mass spectrometry) (Werner & Brand, 2001, Brodie et al. 2011 and Mollenhauer et al., 2021). Additionally, lipid biomarker were extracted, separated, and quantified with wet chemical perpetrations of n-alkanes (Wei, 2020) (quantified with gas chromatography – flame ionization detector), fatty acids (quantified with gas chromatography – flame ionization detector) (Wei, 2020), and GDGTs (Hopmans, 2016) (quantified with gas chromatography – mass spectrometry). Included are datasets of associated biomarker indices of Carbon Preference Index (CPI) (Bray & Evans, 1961), Branched and Isoprenoid Tetraether (BIT) Index (Hopmann et al., 2004), and Terrestrial Aquatic Ratio (TAR) of fatty acids (Meyers, 1997). Further microbial utilization and bio-availability of petrogenic- and marine organic carbon was assed using Intact Polar Lipid (IPL) based compound specific radiocarbon analysis (CSRA) in combination with a DI14C age model of the local surface waters. IPLs were extracted form sediments with a modified Bligh and Dyer (1959) and subsequently separated with wet-chemical seperations (Slater, 2006). CSRA (Mollenhauer et al., 2021) of IPLs was performed on purified single compound fatty acid (FA) methyl esters of the IPL precursor lipids (Wei et al., 2021). The bio-availability of petrogenic organic carbon was based on CSRA data of IPL-FAs using an isotope mass balance with two endmembers of fossil petrogenic and modern marine primary production (DI14C age model of the local surface waters) (Ruben et al., 2022). For the DI14C age model of the local surface waters simulations were run using the Finite-volumE Sea ice-Ocean Model FESOM2 (Danilov et al., 2017) equipped with radiocarbon (Lohmann et al., 2020). Data validity was assessed by relative concentrations of IPLs in the radiocarbon analyzed PL-fraction (Wörmer et al., 2013). Detailed dataset interpretation can be found in Ruben et al. (2023).