Publication Date:
2023-06-27
Description:
A series of molecular organic markers were determined in surface sediments from the Gulf of Genoa (Ligurian Sea) in order to evaluate their potential for palaeo-environmental reconstructions. Allochthonous input can be characterized by the distributions of n-C29 and n-C31 alkanes, n-C26 and n-C28 alkanols and branched glycerol dialkyl glycerol tetraethers (GDGTs), whose concentrations are generally highest near the river mouths. In the open basin however, terrestrial n-alkanes and n-alkanols may have an additional, aeolian source. Autochthonous input is represented by crenarchaeol and isoprenoid GDGTs. Their concentrations are highest in the open basin showing the preference of Thaumarchaeota for oligotrophic waters. Indications of a significant degradation of sterols and C37 alkenones exclude these lipids as reliable productivity proxies. Using terrestrial and aquatic lipids as end-members allows estimating the percentage of terrestrial organic matter between 20% and 58% in the coastal area decreasing to 1 to 30% in the deep basin. The spatial distribution of sea surface temperature (SST) estimates using the alkenone-based UK'37 index is very similar to the autumnal (November) mean satellite-based SST distribution. Conversely, TEXH86-derived SST estimates are close to winter SSTs in the coastal area and summer SSTs in the open basin. This pattern reflects presumably a shift in the main production of Thaumarchaeota from the coastal area in winter to the open basin in summer. This study represents a major prerequisite for the future application of lipid biomarkers on sediment cores from the Gulf of Genoa.
Keywords:
Alkanol preservation index; Alkenone, unsaturation index UK'37; Average chain length; AWI_Paleo; Baltic Sea Research Institute, Warnemünde; Branched and isoprenoid tetraether index; Branched glycerol dialkyl glycerol tetraether, per unit mass total organic carbon; Calculated from TEX86 (Kim et al., 2008); Calculated from TEX86 (Kim et al., 2010); Calculated from UK37 (Conte et al., 2006); Carbon, organic, total; Carbon/Nitrogen ratio; Carbon Preference Index, n-Alkanes; Crenarchaeol, per unit mass total organic carbon; DEPTH, sediment/rock; Elevation of event; Event label; FC; Frahm corer; Higher Plant Alkanes index; IOW; Isoprenoid glycerol dialkyl glycerol tetraether, per unit mass total organic carbon; Latitude of event; Ligurian Sea, Mediterranean; Longitude of event; MUC; MultiCorer; n-Alkane, sum, per unit mass total organic carbon; n-Alkanol, sum, per unit mass total organic carbon; Nitrogen, total; P413; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; POS413; POS413_04-3; POS413_05-1; POS413_06-2; POS413_07-1; POS413_08-7; POS413_09-1; POS413_11-2; POS413_12-1; POS413_15-2; POS413_19-3; POS413_22-3; POS413_24-3; POS413_27-1; POS413_33-3; POS413_35-3; POS413_36-4; POS413_37-4; POS413_38-1; POS413_41-4; POS413_44-3; POS413_45-3; POS413_46-3; POS413_47-3; POS413_49-3; POS413_54-4; POS413_55-3; POS413_57-3; POS413_58-3; POS413_60-1; Poseidon; Sea surface temperature, annual mean; Tetraether index of 86 carbon atoms; Unresolved complex mixture, per unit mass total organic carbon
Type:
Dataset
Format:
text/tab-separated-values, 567 data points
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