Publication Date:
2023-12-18
Description:
The TEX86 paleotemperature proxy is based on the distribution of archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids preserved in marine sediments, yet both the influence of different physiological factors on the structural distribution of GDGTs and the mechanism(s) by which GDGTs is(are) exported to marine sediments remain(s) unresolved. We investigated the abundance and structural distribution of GDGTs in the South-west and Equatorial Atlantic Ocean in four water column profiles spanning 48 degrees of latitude. The depth distribution was consistent with production by ammonia-oxidizing Thaumarchaeota; maximum GDGT concentration occurred at the base of the NO2**- maximum, core GDGTs dominated the structural distribution in surface waters above the NO2**- maximum, and intact polar GDGTs - potentially indicating live cells - were more abundant below the NO2**- maximum. Between 0 and1000 m, 〉 98% of the integrated GDGT inventory was present in waters at and below the NO2**- maximum. Depth profiles of TEX86 temperature values displayed local minima at the NO2**- maximum, while the ratio of GDGT-2:GDGT-3 increased with depth. A model based on the results predicts an average depth of origin for GDGTs exported to sediments between ca. 80-250?m. In the model, exported TEX86 values are remarkably insensitive to change in the average depth of origin of GDGTs. However, TEX86 values exported from the water column appear to reflect euphotic zone productivity, possibly due to the correlative intensity of organic matter remineralization providing substrates for ammonia oxidation. Predicting the influence of these regional controls on sedimentary TEX86 records requires a better understanding of the interaction between GDGT production, particle dynamics, and the depth of origin for exported organic matter.
Keywords:
15; 2; 20130327.2206.001; 20130328.1437.001; 20130329.0154.001; 20130329.2139.001; 20130406.0124.001; 20130406.2328.001; 20130407.1335.001; 20130418.0526.001; 20130418.2200.001; 20130419.1229.001; 20130420.0338.001; 20130503.1831.001; 20130504.0746.001; 20130506.0410.001; 20130506.1639.001; 23; 7; Calculated from TEX86H (Kim et al., 2012); Core acyclic glycerol dialkyl glycerol tetraether; Core crenarchaeol; Core crenarchaeol regio-isomer; Core dicyclic glycerol dialkyl glycerol tetraether; Core monocyclic glycerol dialkyl glycerol tetraether; Core tetracyclic glycerol dialkyl glycerol tetraether; Core tricyclic glycerol dialkyl glycerol tetraether; Date/time end; Date/time start; DEPTH, water; Diglycosyl acyclic glycerol dialkyl glycerol tetraether; Diglycosyl crenarchaeol; Diglycosyl crenarchaeol regio-isomer; Diglycosyl dicyclic glycerol dialkyl glycerol tetraether; Diglycosyl glycerol dialkyl glycerol tetraethers, total; Diglycosyl monocyclic glycerol dialkyl glycerol tetraether; Diglycosyl tetracyclic glycerol dialkyl glycerol tetraether; Diglycosyl tricyclic glycerol dialkyl glycerol tetraether; Event label; Filter; Glycerol dialkyl glycerol tetraethers, total; Hexosephosphohexose acyclic glycerol dialkyl glycerol tetraether; Hexosephosphohexose crenarchaeol; Hexosephosphohexose crenarchaeol regio-isomer; Hexosephosphohexose dicyclic glycerol dialkyl glycerol tetraether; Hexosephosphohexose glycerol dialkyl glycerol tetraethers, total; Hexosephosphohexose monocyclic glycerol dialkyl glycerol tetraether; Hexosephosphohexose tetracyclic glycerol dialkyl glycerol tetraether; Hexosephosphohexose tricyclic glycerol dialkyl glycerol tetraether; KN210-04; Knorr; Latitude of event; Longitude of event; McLane Pump; McLP; Monoglycosyl acyclic glycerol dialkyl glycerol tetraether; Monoglycosyl crenarchaeol; Monoglycosyl crenarchaeol regio-isomer; Monoglycosyl dicyclic glycerol dialkyl glycerol tetraether; Monoglycosyl glycerol dialkyl glycerol tetraethers, total; Monoglycosyl monocyclic glycerol dialkyl glycerol tetraether; Monoglycosyl tetracyclic glycerol dialkyl glycerol tetraether; Monoglycosyl tricyclic glycerol dialkyl glycerol tetraether; Ratio; Sample code/label; Station label; Sum core glycerol dialkyl glycerol tetraethers; Temperature, calculated; Tetraether index of 86 carbon atoms of core glycerol dialkyl glycerol tetraethers; Tetraether index of 86 carbon atoms of diglycosyl glycerol dialkyl glycerol tetraethers; Tetraether index of 86 carbon atoms of glycerol dialkyl glycerol tetraethers; Tetraether index of 86 carbon atoms of hexosephosphohexose glycerol dialkyl glycerol tetraethers; Tetraether index of 86 carbon atoms of monoglycosyl glycerol dialkyl glycerol tetraethers
Type:
Dataset
Format:
text/tab-separated-values, 4751 data points
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