An improvement in the small-volume technique for determining thorium-234 in seawater
MetadataShow full item record
The recently developed 2‐5 L small‐volume MnO2 coprecipitation method for determining 234Th in seawater has provided a new way to substantially increase, both temporally and spatially, the sampling resolution of 234Th and 234Th‐based particulate organic carbon export estimates in the upper ocean. In this study, we further optimize the technique by reducing reagent quantities and the use of an additional water bath heating step. This optimization allows the filtration of the MnO2 precipitate onto a 25‐mm diameter, 1.0 μm pore size QMA filter to be completed within < 30 minutes for unfiltered waters from the South China Sea. In addition, we have modified the MnO2 purification procedure to allow for alpha spetrometric measurements of 234Th recoveries. Results from recovery experiments suggest that reagent amounts can be reduced to 0.0375 mg KMnO4 and 0.1 mg MnCl2∙4H2O per liter of sample, while still maintaining high 234Th recovery. This study further confirms that the addition of a yield monitor is necessary for the application of this small‐volume method.
Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Chemistry 100 (2006): 282-288, doi:10.1016/j.marchem.2005.10.016.
Showing items related by title, author, creator and subject.
Marchal, Olivier; Francois, Roger; Scholten, Jan C. (2007-01-02)An inverse finite-difference model of the abyssal circulation in the North Atlantic Ocean is developed in order to evaluate the dynamical information contained in measurements of thorium-230 (230Th). The model has a very ...
Thorium-234 as a tracer of spatial, temporal and vertical variability in particle flux in the North Pacific Buesseler, Ken O.; Pike, Steven M.; Maiti, Kanchan; Lamborg, Carl H.; Siegel, David A.; Trull, Thomas W. (2009-03-27)An extensive 234Th data set was collected at two sites in the North Pacific: ALOHA, an oligotrophic site near Hawaii, and K2, a mesotrophic HNLC site in the NW Pacific as part of the VERTIGO (VERtical Transport in the ...
Hartman, M. C.; Buesseler, Ken O. (Woods Hole Oceanographic Institution, 1994-07)Two polypropylene cartridge types (Beta Pure and Hytrex II) were tested in the laboratory as adsorbers for in-situ collection of dissolved Thorium-234 (234TH) in seawater. Using a uranyl nitrate tracer, we determined that ...