PUBLICATIONS

*denotes supervised undergraduate or graduate student publication

* denotes supervised undergraduate or graduate student publication

  1. *Lewis C., Walker B.D., Druffel E.R.M. (2021) New radiocarbon constraints on the global cycling of solid-phase extractable dissolved organic carbon. Accepted at Geophysical Research Letters.


  1. Druffel E.R.M., Griffin S., *Lewis C., Rudresh M., *Garcia N., Key R., McNichol A., Hauksson H., Walker B.D. (2021) Dissolved Organic Radiocarbon in the Eastern Pacific and Southern Oceans. Geophysical Research Letters. 48, e2021GL092904. https://doi.org/10.1029/2021GL092904

  1. Vargas C., Cantarero S., Sepulveda J., Galán A., De Pol-Holz R., Walker B.D., Schneider W., Farías L., D’Ottone M.C, Walker J., Xu X., Salisbury J. (2021). A source of isotopically light organic carbon in a low-pH anoxic marine zone. Nature Communications. 12, 1604. https://doi.org/0.1038/s41467-021-21871-4.


  1. Walker B.D., Beaupré S.R., Griffin S., Walker J., Druffel E.R.M., Xu X. (2021). A sealed‐tube method for offline 13C analysis of CO2 via a Gas Bench II continuous‐flow isotope ratio mass spectrometer. Rapid Communications in Mass Spectrometry. 35(7), e9040. https://doi.org/10.1002/rcm.9040.


  1. *Broek, T., Walker, B., Guilderson, T., Vaughn, J., Mason, H., McCarthy, M. (2020). Low Molecular Weight Dissolved Organic Carbon: Aging, Compositional Changes, and Selective Utilization During Global Ocean Circulation Global Biogeochemical Cycles 34(6). https://dx.doi.org/10.1029/2020gb006547


  1. *Lewis CB, Walker BD, Druffel ERM. (2020) Isotopic and optical heterogeneity of solid phase extracted marine dissolved organic carbon, Marine Chemistry, 219. https://doi.org/10.1016/j.marchem.2020.103752


  1. Beaupré SR, Walker BD, Druffel ERM. (2020) The two-component model coincidence: Evaluating the validity of marine dissolved organic radiocarbon as a stable-conservative tracer at Station M, Deep-Sea Research Part II: Topical Studies in Oceanography, 137. https://doi.org/10.1016/j.dsr2.2020.104737


  1. Jeff Chanton, Aprami Jaggi, Jagoš R. Radović, Brad Rosenheim, Brett D. Walker, Stephen R. Larter, Kelsey Rogers, Samantha Bosman, and Thomas B.P. Oldenburg. (2020) Mapping isotopic and dissolved organic matter baselines in waters and sediments of the Gulf of Mexico. In Scenarios and Responses to Future Deep Oil Spills – Fighting the Next War. Springer Nature Publishing.


  1. Druffel E.R.M., Griffin S., Wang N., Garcia N., McNichol A.P., Key R.M., Walker B.D. (2019) Dissolved Organic Radiocarbon in the Central Pacific Ocean. Geophysical Research Letters (46). https://doi.org/10.1029/2019GL083149


  1. *Shammas N., Walker B., Martinez De La Torre H., Bertrand C., Southon J. (2019) Effects of Acid Strength and Duration during Decalcification of Archaeological Bone and Ultrafiltration Preparation on Collagen Yield. Nuclear Instruments and Methods in Physics Research Section B. https://doi.org/10.1016/j.nimb.2019.01.018


  1. Walker, B.D., Beaupré S.R., Griffin, S., Druffel E.R.M. (2019) UV photochemical oxidation and extraction of marine dissolved organic carbon at UC Irvine: status, surprises, and methodological recommendations. Radiocarbon, 61 (5). https://doi.org/10.1017/RDC.2019.9


  1. Walker, B.D., Xu, X. (2019) An improved method for sealed tube zinc graphitization of microgram carbon samples for AMS 14C measurement. Nuclear Instruments and Methods in Physics Research Section B. (438) p. 58-65. https://doi.org/10.1016/j.nimb.2018.08.004


  1. Druffel, E.R.M., Griffin, S., Wang, N., Walker B.D. (2018) Temporal variability of dissolved organic radiocarbon in the deep North Pacific Ocean. Radiocarbon (60) 4. p. 1115-1123. https://doi.org/10.1017/RDC.2018.39


  1. *S. Fatayer, *A. Coppola, F. Schulz, B. Walker, T. Broek, G. Meyer, E. R. M. Druffel, M. McCarthy and L. Gross. (2018) Determining aromatic compounds in marine dissolved organic carbon with atomic force microscopy. Geophysical Research Letters, 45 (11) p. 5590-5598. https://doi.org/10.1029/2018GL077457


  1. Walker, B.D., E.R.M. Druffel, J. Kolasinski, B. Roberts, X. Xu, B. Rosenheim. (2017) Stable and radiocarbon isotopic composition of dissolved organic carbon in the Gulf of Mexico. Geophysical Research Letters, 44 (16) p. 8424–8434. https://doi.org/10.1002/2017GL074155


  1. *Broek, T.A.B., B.D. Walker, T.P. Guilderson, M.D. McCarthy. (2017) Coupled ultrafiltration and solid phase extraction approach for the targeted study of semi-labile high molecular weight and refractory low molecular weight dissolved organic matter. Marine Chemistry. 194 p. 146-157. https://doi.org/10.1016/j.marchem.2017.06.007


  1. Druffel, E.R.M., Griffin, S., Glynn, C.S., Benner, R., Walker B.D. (2017) Radiocarbon in dissolved organic and inorganic carbon of the Arctic Ocean. Geophysical Research Letters. 44 (4) https://doi.org/10.1002/2016GL072138


  1. Walker B.D., Beaupre, S.B., T.P. Guilderson, M.D. McCarthy, E.R.M. Druffel. (2016) Pacific carbon cycling constrained by organic matter size, age, and composition relationships. Nature Geoscience. 9 p. 888-891. https://doi.org/10.1038/NGEO2830

Featured in Amon, R. (2016) Carbon cycle: Ocean dissolved organic matter. Nature Geoscience: News and Views 9, p. 864–865. https://doi.org/10.1038/ngeo2841


  1. Walker B.D., F.W. Primeau, S.R. Beaupre, T.P. Guilderson, E.R.M. Druffel, M.D. McCarthy. (2016) Linked changes in marine dissolved organic carbon molecular size and radiocarbon age. Geophysical Research Letters. 43 (19) p. 10385–10393. https://doi.org/10.1002/2016GL070359


  1. Walker B.D., Griffin, S.M., Druffel, E.R.M. (2016) Effect of acidified versus frozen storage on marine dissolved organic carbon concentration and isotopic composition. Radiocarbon. https://doi.org/10.1017/RDC.2016.48


  1. Druffel, E.R.M., Griffin, S., Coppola, A.I., Walker B.D. (2016) Radiocarbon in dissolved organic carbon of the Atlantic Ocean. Geophysical Research Letters. 43 (10), p. 5279–5286. https://doi.org/10.1002/2016GL068746


  1. *Bour, A., Walker, B.D., Broek T.B., McCarthy M.D. (2016) Radiocarbon analysis of individual amino acids: carbon blank quantification for a small-sample high pressure liquid chromatography purification method. Analytical Chemistry 88 (7), p. 3521–3528. https://doi.org/10.1021/acs.analchem.5b03619


  1. *Coppola, A.I., Walker, B.D., Druffel, E.R.M. (2015) A solid phase extraction method for compound-specific radiocarbon analyses of black carbon in dissolved organic carbon. Marine Chemistry (177) part 5, p. 697-705. https://doi.org/10.1016/j.marchem.2015.10.010


  1. Walker B.D., T.P. Guilderson, K.M. Okimura, M.B. Peacock, M.D. McCarthy. (2014) Radiocarbon signatures and size-age-composition relationships of major organic matter pools within a unique California upwelling system. Geochimica et Cosmochimica Acta (126) p.1-17. https://doi.org/10.1016/j.gca.2013.10.039


  1. *Broek, T.A.B., B.D. Walker, D.H. Andreasen, T.P. Guilderson, M.D. McCarthy. (2013) High-precision measurement of phenylalanine 15N values for environmental samples: A new approach coupling high-pressure liquid chromatography purification and elemental analyzer isotope ratio mass spectrometry. Rapid Commun. Mass Spectrom. (27) p.2327-2337. https://doi.org/10.1002/rcm.6695


  1. Druffel E.R.M., S.M Griffin, B.D. Walker, A. Coppola, D. Glynn. (2013) Total Uncertainty of Radiocarbon Measurements of Marine Dissolved Organic Carbon and Methodological Recommendations. Radiocarbon (55) 2-3 p.1135-1141. https://doi.org/10.1017/S0033822200048049


  1. Bertrand C., B.D. Walker, S.M. Griffin, E.R.M. Druffel. (2013) Comparison of radiocarbon in particulate organic carbon and dissolved inorganic carbon from the surface Northeast Pacific Ocean. Radiocarbon (55) 2-3 p.1651-1658. https://doi.org/10.1017/S0033822200048566


  1. Walker B.D., M.D. McCarthy. (2012) Elemental and isotopic characterization of dissolved and particulate organic matter in a unique California upwelling system: Importance of size and composition in the export of labile material. Limnology and Oceanography 57(6) p.1757-1774. https://doi.org/10.4319/lo.2012.57.6.1757


  1. Walker B.D. (2011) New radiocarbon and size-fractionation approaches for examining organic matter source and reactivity in the sea. Dissertation, University of California, Santa Cruz.


  1. Walker B.D., S.R. Beaupre, T.P. Guilderson, E.R.M. Druffel, M.D. McCarthy. (2011) Large-volume ultrafiltration for the study of marine dissolved organic matter radiocarbon signatures. Geochimica et Cosmochimica Acta (75) p.5187-5202. https://doi.org/https://doi.org/10.1016/j.gca.2011.06.015


  1. Christian A. Miller, Bernhard Peucker-Ehrenbrink, Brett D. Walker, Franco Marcantonio. (2011) Re-assessing the surface cycling of molybdenum and rhenium. Geochimica et Cosmochimica Acta (75) p.7146-7179. https://doi.org/https://doi.org/10.1016/j.gca.2011.09.005


  1. McCarthy M.D., Beaupre S.R., Walker B.D., Voparil, I., Guilderson, T.P., Druffel, E.R.M. (2011) Chemosynthetic 14C-depleted dissolved organic carbon in a ridge-flank hydrothermal system. Nature Geoscience (4) p.32-36. https://doi.org/10.1038/NGEO1015

  1. Roland L.A., McCarthy M.D., Peterson T.D., Walker B.D. (2009) A large-volume micro-filtration system for isolating suspended particulate organic matter: fabrication and assessment vs. GFF filters in central N. Pacific. L&O Methods (7) p.64-80. https://doi.org/ https://doi.org/10.4319/lom.2009.7.64


  1. Walker B.D., McCarthy M.D., Fisher A.T., Guilderson T.P. (2008) Dissolved inorganic carbon isotopic composition of low-temperature axial and ridge-flank hydrothermal fluids of the Juan de Fuca Ridge. Marine Chemistry (108) p. 123-136. https://doi.org/https://doi.org/10.1016/j.marchem.2007.11.002