CHESAPEAKE BAY  EXPEDITION

In this study, we will evaluate in natural environment, the fidelity with which alkenones record the D/H ratio of water in which they are synthesized and the impact of salinity on D/H fractionation during alkenone biosynthesis.

Purpose

The aim of this study is to demonstrate that alkenone D/H ratios can be used to reconstruct paleohydrologic conditions and sea surface salinity. It is well known that  biomarker δD values can be used to determine the D/H ratios of water in which the compounds were synthesized (e.g. Sachse et al., 2004 [PDF];  Sauer et al., 2001). In culture experiments, Englebrecht and Sachs, 2005 [PDF] have demonstrated a near-perfect linear correlation between salinity and water δD, and alkenone δD and water δD.

Near-perfect linear correlation between alkenone δD from culture experiment and the δD values of the source water (Englebrecht and Sachs, 2005).

Alkenones, and related alkyl alkenoates and alkanes are synthesised by coccolithophore (haptophyte algae of the Order Isochrysidales) such as the cosmopolite Emiliania huxleyi and the closely related species.

 

C₃₇ alkenone