Contact Information
Research Areas
Research Description
Prof. Johnson's group focuses on environmental geochemistry, isotope geochemistry, and hydrogeology. The group is working to better understand several redox-sensitive contaminant elements, including chromium, selenium, uranium, and mercury. They develop and use methods for measurement of the stable isotopes of these and other elements as indicators of key geochemical reactions, contamination sources, and past environments on Earth.
The group uses the department's multicollector ICP-MS laboratory constantly to make these measurements and often develops or improves measurement methods.
Education
Ph.D., University of California at Berkeley
Courses Taught
- GEOL 117: The Oceans
- GEOL 118: Natural Disasters
- GEOL 370/GEOG 370/ESE 320: Water Planet/Water Crisis
- GEOL 470: Hydrogeology
- GEOL 562: Isotope Geochemistry
- GEOL 579: Isotope Hydrogeology
Additional Campus Affiliations
Professor, Earth Science and Environmental Change
External Links
Recent Publications
Hendry, M. J., Johnson, T. M., Schmeling, E., Shaw, S., & Kirk, L. (2024). Application of selenium isotopes to define selenium bioreduction in coal waste rock: Elk Valley, British Columbia. Science of the Total Environment, 957, Article 177838. https://doi.org/10.1016/j.scitotenv.2024.177838
Zhu, J. M., Sun, W., Johnson, T. M., Lu, Z., & Tan, D. (2024). Correction Strategies for Isotopic Ratios in Overspiked Samples Using the Double Spike Technique. Analytical Chemistry, 96(50), 19965-19971. https://doi.org/10.1021/acs.analchem.4c04391
Crowley, B. E., Bruff Simpson, E. M., Hammer, S. J., Smith, J. M., & Johnson, T. M. (2023). Comparison of powdered enamel sample pretreatment methods for strontium isotope analysis. Frontiers in Environmental Chemistry, 4, Article 1114807. https://doi.org/10.3389/fenvc.2023.1114807
Lu, Z., Zhu, J. M., Tan, D., Johnson, T. M., & Wang, X. (2023). Double Spike-Standard Addition Technique and Its Application in Measuring Isotopes. Analytical Chemistry, 95(4), 2253-2259. https://doi.org/10.1021/acs.analchem.2c03802
Veldhuizen, H. J., MacKinney, J. S., & Johnson, T. M. (2023). Kinetic Fractionation of Antimony Isotopes during Reduction by Sulfide. ACS Earth and Space Chemistry, 7(12), 2603-2612. https://doi.org/10.1021/acsearthspacechem.3c00269