Award: OCE-0961579

This proposal allowed the Bruland research group at UC Santa Cruz to continue their involvement in the GEOTRACES program during the US North Atlantic zonal section. We were responsible for a number of activities: Geoffrey Smith and the UCSC clean van and clean GeoFish allowed the collection of large volumes of clean surface seawater for a wide variety of investigators. We collected an extensive set of surface seawater samples for the analysis of a large suite of dissolved trace metals. Claire Parker, a graduate student in our research group, is currently finishing these analyses. These samples will provide an extensive set of surface water data over the North Atlantic that will be complementary to the atmospheric aerosol studies and will provide valuable data for modelers. We collected an archive of vertical profile samples in rigorously cleaned, 0.5 liter, low density, polyethylene bottles. This is a library of over 600 samples. We analyzed a suite of metals at the Super Stations to facilitate an intercomparison study with other GEOTRACES analysts. This involved an evaluation of the clean sampling systems developed for the GEOTRACES program and an evaluation of the analytical methods used for the determination of dissolved metals. An example of this is shown in the figure included for dissolved cadmium. This figure shows the excellent agreement between the Netherlands GEOTRACES program and the US GEOTRACES program on a common crossover station – the BATS station near Bermuda. The figure also shows the excellent agreement between three different US labs analyzing Cd (Univ. of South Carolina, John and Conway; Univ. of Miami, Wu; UC Santa Cruz, Middag and Bruland). This intercomparison was to help address quality control issues with the emerging data sets for this global program. We have similar data for a suite of different dissolved trace metals including iron, zinc, lead, manganese, cobalt, nickel, copper and gallium. We have continued to supply a variety of important SAFe and GEOTRACES seawater reference samples to the US and International GEOTRACES community and continually upgrade the consensus values and lists of participating scientists and their methods. This has been invaluable in helping researchers in other countries develop their analytical capabilities in the GEOTRACES program. The proposal provided training for a post doctoral researcher and two graduate students. Dr. Rob Middag, the post doc, is now in a faculty position at the University of Otago in Dunedin, New Zealand. Dondra Biller has a 2012 publication from this research and will be defending her Ph.D. at the end of February 2013. Claire Parker is a second year Ph.D. student in the midst of data analysis. Last Modified: 02/13/2013 Submitted by: Kenneth W Bruland