Recent advances in accelerator mass spectrometry have greatly reduced the sample size (from several grams of C to tens of micrograms of C) requirement for determining ¹⁴C-ages of organic substances. It is now possible to obtain ¹⁴C-ages for specific organic compounds (compound-specific radiocarbon analyses - csra) through the pioneering work of Dr. Timothy Eglinton at WHOI and the National Ocean Science Accelerator Mass Spectrometer (NOSAMS) facility. We have acquired a Gerstel preparative capillary gas chromatograph (PCGC) fraction collector system that is now operating for collection of individual compounds for AMS dating in collaboration with the WHOI groups.

This is an exciting new area for our group, and further information will be available as we begin to explore the ¹⁴C-ages of lipid biomarkers in a number of interesting environments. For example, we are tracking the flow of fossil carbon into bacterial biomass by determining apparent ¹⁴C ages of bacteria-specific membrane polar lipid fatty acid biomarkers in a marsh sediment that is chronically polluted by petroleum (having an infinite ¹⁴C age) compared to a pristine sediment (with contemporary ¹⁴C age). Radiocarbon ages of biomarkers in oceanic particulate matter and surface sediments may also help to resolve questions about incorporation of old dissolved organic matter into particulate material and causes of non-zero ¹⁴C ages for surface sediments . We currently have a project using csra to characterize the sources and behavior sinking particulate and sedimentary organic carbon.