The goals of our research are twofold.

First,we seek to understand why the ¹⁴C age of marine dissolved organic carbon (DOC) is thousands of years old, despite evidence that most of it is produced in the surface ocean during photosynthesis. Is black carbon, produced on land, a significant source of old oceanic DOC?

Second, how has circulation changed in the tropical and subtropical Pacific during the past millennium? We use accelerator mass spectrometry (AMS) and preparative capillary gas chromatography (PCGC) at the Keck Carbon Cycle AMS Lab to measure radiocarbon in samples as small as 2µg C. We study corals from the Galapagos, Palmyra Atoll, the Great Barrier Reef, Bermuda and other sites to reconstruct seasonal-to-annual records of isotopes that reveal past temperature, salinity and upwelling strength in surface waters.