Dataset: GP15 Dissolved and Particulate Mercury Leg 1

This dataset includes the results of analyzing water and particulate samples collected by the US GEOTRACES scientific crew on the GP15 expedition on R/V Roger Revelle, which took place from September 18 to November 24, 2018. This dataset is valuable for the insights it provides concerning an acute environmental toxicant whose biogeochemical cycle has been dramatically affected by human activity. Of particular value is the wide range of biogeochemical conditions spanned by the transect (from Alaska to Tahiti) providing opportunities to observe the impact of various sources, sinks, and forces driving the internal cycling of this metal. The samples were preserved on-board and then returned to our home institutions (Wright State University and the University of Connecticut) where they were further processed and mercury species were determined. Filtered water samples for both total mercury (HgT; the sum of Hg2+, Hg0, CH3Hg+ and (CH3)2Hg; 200 milliliters (mL)) and total methylated mercury (MeHg; the sum of CH3Hg+ and (CH3)2Hg; 200 mL) were obtained from the US GEOTRACES Clean Rosette and processed in a clean van on board. The particulate complementary species, particulate HgT and MeHg, were determined on subsamples (13-millimeter diameter "punches") of quartz-fiber filters deployed on battery-operated, in situ pumps. Analysis followed EPA Standard Methods for these species using high-sensitivity Cold Vapor Atomic Fluorescence Spectrometry detection. The analysts were Dr. Lindsay Starr (at Wright State) and Dr. Yipeng He (at University of Connecticut). The expedition was divided into two legs, with cruise IDs RR1814 and RR1815. This dataset results from leg 1, RR1814; data from RR1815 are available in a separate BCO-DMO dataset.