I am an isotope geochemist and study the cycling of trace metals in the environment. My main research interests are;
–Studying organic carbon cycling in the ocean using barium isotope variations
The cycling of organic carbon in the ocean plays an important role in modulating global climate. The production and export of particulate organic carbon by photosynthetic organisms sequesters atmospheric CO2 into the deep ocean and marine sediments. Some of this organic carbon is converted to methane in deeply buried sediments, so that marine sediments host vast amounts of this potent greenhouse gas. This methane reservoir is vulnerable to environmental change, and can potentially release large amounts of methane into the ocean and atmosphere.
I am interested in developing barium isotope variations as a powerful tracer to study:
(1) The role of organic carbon production and export in the past ocean for sequestering atmospheric CO2 during periods of abrupt climatic change (e.g. during the Paleocene-Eocene Thermal Maximum)
(2) Changes in seafloor methane leakage in response to changing environmental conditions (i.e. seawater temperature and sea level)
–The perturbation of trace metal cycling in the atmosphere, oceans and rivers by human activities
Human activities such as mining and fossil fuel combustion have been a major source of numerous trace metals to the environment during the past century. Due to the toxicity of many of these metals at high enough concentrations and certain chemical forms, anthropogenic inputs can be a cause of concern for public health. The addition of anthropogenic trace metals to environmental systems can also be used to understand natural processes. For example, temporally changing inputs of lead to the ocean from leaded petrol usage can be used to understand the rates and pathways of ocean ventilation, which has been a research interest of mine. I am also involved in an on-going project to survey the concentrations of potentially toxic trace metals in rivers in Myanmar, and help identify potential pollution problems faced by this developing nation.
View Selected Publications
L. Bridgestock, M. Rehkämper, T. van de Flierdt, M. Paul, A. Milne, M. Lohan, E. Achterberg, 2018, The distribution of lead concentrations and isotope compositions in the eastern Tropical Atlantic Ocean, Geochimica et Cosmoschimica Acta, 225, 36-51, doi.10.1016/j.gca.2018.01.018
L. Bridgestock, Y-T. Hsieh, D. Porcelli, W. B. Homoky, A. Bryan & G. M. Henderson, 2018, Controls on the barium isotope compositions of marine sediments, Earth and Planetary Science Letters, 481, 101-110, doi.10.1016/j.epsl.2017.10.019
L. Bridgestock, M. Rehkämper, T. van de Flierdt, K. Murphy, Khondoker, A. Baker, R. Chance, E. Achterberg, 2017, The Cd isotope composition of atmospheric aerosols, Geophysical Research Letters, 44, doi:10.1002/2017/GL072748
L. Bridgestock, T. van de Flierdt, M. Rehkämper, M. Paul, R. Middag, A. Milne, M. C. Lohan, A. R. Baker, R. Chance, R. Khondoker, S. Strekopytov, E. Humphreys-Williams, E. P. Achterberg, M. J. A. Rijkenberg, L. J. A. Gerringa & H. J. W. de Baar, 2016, Return of naturally sourced Pb to Atlantic surface waters, Nature Communications, doi:10.1038/ncomms12921
M. Paul, L. Bridgestock, M. Rehkämper, T. van de Flierdt, D. J. Weiss, 2015, High-precision measurements of seawater Pb isotope compositions by double-spike thermal ionization mass spectrometry, Analytica Chimica Acta, 863, 59-69
L. J. Bridgestock, H .Williams, M. Rehkämper. F. Larner, M.D. Giscard, S. Hammond, B. Coles, R. Andreasen, B. J. Wood, K. J. Theis, C. L. Smith, G. K. Benedix, M. Schonbachler, 2014, Unlocking the zinc isotope systematics of iron meteorites, Earth and Planetary Science Letters, 400, 153-164
F. Larner, Y. Dogra, A. Dybowska, J. Fabrega, B. Stolp, L. J. Bridgestock, R. Goodhead, D. J. Weiss, J. Moger, J. R., Lead, E. Valsami-Jones, C. R. Tyler, T. S. Galloway, M. Rehkämper, 2012, Tracing bioavailability of ZnO nanoparticles using stable isotope labeling, Environmental Science & Technology, 42, 12137-12145