Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
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Volume 12, issue 22
Biogeosciences, 12, 6573–6590, 2015
https://doi.org/10.5194/bg-12-6573-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 12, 6573–6590, 2015
https://doi.org/10.5194/bg-12-6573-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 19 Nov 2015

Research article | 19 Nov 2015

Constraints on the applicability of the organic temperature proxies UK'37, TEX86 and LDI in the subpolar region around Iceland

M. Rodrigo-Gámiz1,a, S. W. Rampen1, H. de Haas2, M. Baas1, S. Schouten1, and J. S. Sinninghe Damsté1 M. Rodrigo-Gámiz et al.
  • 1NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, P.O. Box 59, 1790 AB Den Burg, Texel, the Netherlands
  • 2NIOZ Royal Netherlands Institute for Sea Research, Marine Research Facilities, Den Burg, Texel, the Netherlands
  • apresent address: Instituto Andaluz de Ciencias de la Tierra (IACT), CSIC-Universidad de Granada, Granada, Spain

Abstract. Subpolar regions are key areas for studying natural climate variability due to their high sensitivity to rapid environmental changes, particularly through sea surface temperature (SST) variations. Here, we have tested three independent organic temperature proxies (UK'37; TEX86; and the long-chain diol index, LDI) regarding their potential applicability for SST reconstruction in the subpolar region around Iceland. UK'37, TEX86 and TEXL86 temperature estimates from suspended particulate matter showed a substantial discrepancy with instrumental data, while long-chain alkyl diols were below the detection limit at most of the stations. In the northern Iceland Basin, sedimenting particles revealed a seasonality in lipid fluxes, i.e., high fluxes of alkenones and glycerol dialkyl glycerol tetraethers (GDGTs) were measured during late spring and during summer and high fluxes of long-chain alkyl diols during late summer. The flux-weighted average temperature estimates had a significant negative (ca. 2.3 °C for UK'37) and positive (up to 5 °C for TEX86) offset with satellite-derived SSTs and temperature estimates derived from the underlying surface sediment. UK'37 temperature estimates from surface sediments around Iceland correlate well with summer mean sea surface temperatures, while TEX86-derived temperatures correspond with both annual and winter mean 0–200 m temperatures, suggesting a subsurface temperature signal. Anomalous LDI-SST values in surface sediments and low mass flux of 1,13- and 1,15-diols compared to 1,14-diols suggest that Proboscia diatoms are the major sources of long-chain alkyl diols in this area rather than eustigmatophyte algae, and therefore the LDI cannot be applied in this region.

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This research reports a test of the applicability of three organic-derived temperature proxies (UK'37, TEX86 and LDI) at high latitudes around Iceland. A range of samples including suspended particular material (SPM), trapped descending particles and surface sediments were collected to test the different proxies in the water column and the sediment.The combination of three independent SST organic proxies provided important information about seasonality and differences in habitat depth.
This research reports a test of the applicability of three organic-derived temperature proxies...
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