• Compound-Specific Radiocarbon Analyses of Phospholipid Fatty Acids and n-Alkanes in Ocean Sediments

      Druffel, Ellen R. M.; Zhang, Dachun; Xu, Xiaomei; Ziolkowski, Lori A.; Southon, John R.; Dos Santos, Guaciara M.; Trumbore, Susan E. (Department of Geosciences, The University of Arizona, 2010-01-01)
      We report compound-specific radiocarbon analyses of organic matter in ocean sediments from the northeast Pacific Ocean. Chemical extractions and a preparative capillary gas chromatograph (PCGC) were used to isolate phospholipid fatty acids (PLFA) and n-alkanes from 3 cores collected off the coast of California, USA. Mass of samples for accelerator mass spectrometry (AMS) 14C analysis ranged from 13-100 g C. PLFA extracted from anaerobic sediments in the Santa Barbara Basin (595 m depth) had modern ∆14C values (-20 to +54), indicating bacterial utilization of surface-produced, post-bomb organic matter. Lower ∆14C values were obtained for n-alkanes and PLFA from coast (92 m depth) and continental slope (1866 m) sediments, which reflect sources of old organic matter and bioturbation. We present a brief analysis of the blank carbon introduced to samples during chemical processing and PCGC isolation.