Constraints on the applicability of the organic temperature proxies U K' 37 , TEX 86 and LDI in the subpolar region around Iceland

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