Final Report Summary - DIOLS (Long chain diols as novel organic proxies for paleoclimate reconstructions)
The reconstruction of past climate conditions are of importance for predicting the rate and impact of the currently ongoing climate change. In this project we developed and tested a new set of tools based on specific compounds, long chain diols, which enables the accurate reconstruction of past climate conditions. We developed new analytical protocols to analyse these compounds robustly. Using genetic and cultivation techniques we established the sources of these biomarker lipids, in particular in lakes and rivers, and found that the compounds are a robust component of the outer cell wall of certain algae. We also test potential problems such as selective compound degradation and lateral transport but these do not seem to pose a major bias on proxies based on long chain diols. In the end, three major proxies were developed and tested. The first is based on the C14 diols and can be used to reconstruct past productivity of Proboscia diatoms. Secondly, a proxy based on the C32 1,15 diol was developed which enables the reconstruction of riverine input in marine coastal environments. The third proxy is based on C13 and C15-diols, the so-called LDI, and which was shown to reconstruct past sea surface temperatures. Finally, the tested and developed proxies were applied to reconstruct past paleoceanographic conditions from a variety of regions and shown to reveal new information on past climate changes.