Long chain diols and diol indices of surface sediments of the Iberian Atlantic margin (Version 1, 2016-10-07)

DOI

Long chain diols are lipids that have gained interest over the last years due to their high potential to serve as biomarkers and diol indices have been proposed to reconstruct upwelling conditions and sea surface temperature (SST). However, little is known about the sources of the diols and the mechanisms impacting their distribution. Here we studied the factors controlling diol distributions in the Iberian Atlantic margin, which is characterized by a dynamic continental shelf under the influence of upwelling of nutrient-rich cold deep waters, and fluvial input. We analyzed suspended particulate matter (SPM) of the Tagus river, marine SPM and marine surface sediments along five transects off the Iberian margin, as well as riverbank sediments and soil from the catchment area of the Tagus river. Relatively high fractional abundances of the C32 1,15-diol (normalized with respect to the 1,13- and 1,15-diols) were observed in surface sediments in front of major river mouths and this abundance correlates strongly with the BIT index, a tracer for continental input of organic carbon. Together with an even higher fractional abundance of the C32 1,15-diol in the Tagus river SPM, and the absence of long chain diols in the watershed riverbank sediments and soils, we suggest that this long chain diol is produced in-situ in the river. Further support for this hypothesis comes from the small but distinct stable carbon isotopic difference of 1.3 per mil with the marine C28 1,13-diol. The 1,14-diols are relatively abundant in surface sediments directly along the northern part of the coast, close to the upwelling zone, suggesting that Diol Indices based on 1,14-diols would work well as upwelling tracers in this region. Strikingly, we observed a significant difference in stable carbon isotopic composition between the monounsaturated C30:1 1,14- and the saturated C28 1,14-diol (3.8±0.7 per mil), suggesting different sources, in accordance with their different distributions. In addition, the Long chain Diol Index (LDI), a proxy for sea surface temperature, was applied for the surface sediments. The results correlate well with satellite SSTs offshore but reveal a significant discrepancy with satellite-derived SSTs in front of the Tagus and Sado rivers. This suggests that river outflow might compromise the applicability of this proxy.

This dataset was updated on 2019-01-25, please see:https://doi.pangaea.de/10.1594/PANGAEA.897673

Identifier
DOI https://doi.org/10.1594/PANGAEA.865319
Related Identifier IsObsoletedBy https://doi.org/10.1594/PANGAEA.897673
Related Identifier References https://doi.org/10.1016/j.orggeochem.2016.09.005
Related Identifier References https://doi.org/10.1016/j.csr.2015.01.006
Related Identifier References https://doi.org/10.4319/lo.2013.58.1.0343
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.865319
Provenance
Creator de Bar, Marijke W; Dorhout, Denise J C; Hopmans, Ellen C ORCID logo; Rampen, Sebastiaan W ORCID logo; Sinninghe Damsté, Jaap S ORCID logo; Schouten, Stefan
Publisher PANGAEA
Publication Year 2016
Rights Licensing unknown: Please contact principal investigator/authors to gain access and request licensing terms; Data access is restricted (moratorium, sensitive data, license constraints)
OpenAccess false
Representation
Resource Type Dataset
Format text/tab-separated-values
Size 390 data points
Discipline Earth System Research
Spatial Coverage (-10.216W, 38.226S, -8.695E, 41.243N); Portuguese Margin
Temporal Coverage Begin 2011-07-12T00:00:00Z
Temporal Coverage End 2012-05-24T00:00:00Z