Mr Yu-Te (Alan) Hsieh

Postgraduate Student

Email:	yuteh@earth.ox.ac.uk
TEL:	+44 (1865) 272049
FAX:	+44 (1865) 272072

Research Profile

My research is focused on the use of U-Th series isotopes as tracers to study ocean mixing and the inputs of trace metals and nutrients to the open ocean from atmospheric dust, rivers, continental shelves and marine sediments.

²³²Th and ²³⁰Th as tracers for dust input to the oceans

Aeolian dust is a significant source of iron and other nutrients to the surface ocean, but constraining the size of this flux is difficult. ²³²Th (like Al) is a fingerprint of dust deposition to the open ocean. ²³⁰Th provides an assessment of the removal rates of Th isotopes, and therefore allows quantification of the input of dust ²³²Th and dust flux to the surface ocean.

Ra isotopes as tracers for ocean mixing and nutrient inputs

Radium has four isotopes with a wide range of half-lives (²²⁶Ra, T_1/2 = 1600 years; ²²⁸Ra, T_1/2 = 5.75 years; ²²³Ra, T_1/2 = 11.4 days; ²²⁴Ra, T_1/2 = 3.66 days) in the natural environments, which enables us to study oceanic processes at different time scales. The distribution of ²²⁸Ra in the oceans is dominated by ocean mixing and radioactive decay, which enables us to study mixing rates and nutrient fluxes in the oceans.

Selected Publications

Hsieh, Y.-T., Henderson, M.G., and Thomas, L.A. (2011) Combining seawater ²³²Th and ²³⁰Th concentrations to determine dust fluxes to the sufrace ocean. Earth Planet Sci. Lett., 312. 280-290. http://dx.doi.org/10.1016/j.epsl.2011.10.022

Hsieh, Y.-T. and Henderson, G. (2011) Precise measurement of ²²⁸Ra/²²⁶Ra ratios and Ra concentrations in seawater samples by multi-collector ICP mass spectrometry. J. Anal. At. Spectrom. 26. 1338-1346. DOI:10.1039/C1JA10013K