Long chain 1,13- and 1,15-diols as a potential proxy for palaeotemperature reconstruction

• Published in: Geochimica et cosmochimica acta 2012-05, Vol.84, p.204-216
• Main Authors: Rampen, Sebastiaan W., Willmott, Verónica, Kim, Jung-Hyun, Uliana, Eleonora, Mollenhauer, Gesine, Schefuß, Enno, Sinninghe Damsté, Jaap S., Schouten, Stefan
• Format: Article
• Language: English
• Subjects: environmental factors; freshwater; lipids; nutrient content; rivers; salinity; sediments; surface water temperature
• ISSN: 0016-7037; 1872-9533
• DOI: 10.1016/j.gca.2012.01.024

Although commonly reported in marine and freshwater environments, little is known about the biological sources of long chain alkyl 1,13- and 1,15-diols, and factors controlling their distributions. Here we analyzed the occurrence and distribution of these lipids in a comprehensive set of marine surface sediments and compare their distributions with environmental conditions like sea surface temperature (SST), salinity and nutrient concentrations. Fractional abundances of the C28 1,13-, C30 1,13- and C30 1,15-diols show a strong correlation with SST and based on these results, we propose the Long chain Diol Index (LDI), which expresses the C30 1,15-diol abundance relative to those of C28 1,13-, C30 1,13- and C30 1,15-diols. The LDI shows a strong linear correlation with SST (LDI=0.033×SST+0.095; R2=0.969, n=162) over a temperature range of −3 to 27°C. Long chain diol distributions in sediments from the South Atlantic close to the Congo River outflow (West Africa) provided a 43kyr LDI SST record. This record reflects several known climatic events and shows similarities with an alkenone-derived SST record obtained using the same suite of sediments, both in trend and in terms of absolute SST. This confirms the potential of the LDI as a proxy for palaeo-SST reconstruction.