Focus:
Environmental Engineering
Website:
Education:
- Ph.D. Environmental and Water Resources Engineering, University of Texas Austin (2009)
- M.S.E. Civil Engineering, University of Texas Austin (2005)
- B.S.E. Environmental Engineering, Princeton University (2003)
Academic & Professional Experience:
- Assistant/Associate Professor, University of Minnesota Duluth (2009-present)
- Associate, Institute on the Environment - University of Minnesota (2019-present)
- Graduate Faculty, Water Resources Science Program (2010-present)
- Visiting Researcher, Norwegian Water Research Institute, Oslo, Norway 2007, 2017
Research Interests:
We study how sulfur and iron interact in sediments to transform and mobilize contaminants, especially at dynamic redox interfaces. All our projects are related to developing management strategies for water quality challenges in natural and engineered systems and involve partners from natural resource management agencies. We study fundamental and practical aspects of environmental aquatic chemistry, sediment biogeochemistry, and biological and chemical processes related to contaminant transport and transformations, usually applied to mercury and trace organics. We typically complement field or laboratory investigations with mathematical modeling.
Courses Taught:
- CE 3025 Environmental Engineering
- CE 4237/5237 Water Quality Engineering
- CE 5215 Decision, Risk and Reliability
- CE 5241 Water Chemistry
- CE 8020 Graduate Seminar
News About Dr. Johnson's Group:
- Amber White receives prestigious NSF Graduate Research Fellowship
- Dr. Johnson’s team explains mercury contamination in the St Louis River Estuary
- Do not eat: Researchers seek clues on mercury in the St Louis River Estuary
Select Publications & Products:
Full publication list also available on Google Scholar
- Jones DS, *Walker GM, Johnson NW, Mitchell CPJ, Coleman Wasik JK, Bailey JV (2019) Molecular evidence for novel mercury methylating microorganisms in sulfate-impacted lakes. ISME Journal. (13) 1659– 1675.
- Johnson NW, Pastor J, Swain, EB. (2019) Cumulative sulfate loads shift porewater to sulfidic conditions in freshwater wetland sediment. Environmental Toxicology and Chemistry. 38(6) 1231–1244.
- *LaFond-Hudson S, Johnson NW, Pastor J, Dewey B. (2018) Iron sulfide formation on root surfaces controlled by the life cycle of wild rice (Zizania palustris). Biogeochemistry. 141(1)95-106.
- *Brennan A, Johnson NW. (2018) The utility of SPME in evaluating contaminant bioavailability during habitat restoration with dredged material at moderately contaminated sites. Integrated Environmental Assessment and Management. 14(2) 212-223.
- Myrbo A, Swain EB, Johnson NW, Engstrom DR, Pastor J, Dewey B, Monson P, Brenner J, Dykhuizen Shore M, Peters EB. (2017) Increase in nutrients, mercury, and methylmercury as a consequence of elevated sulfate reduction to sulfide in experimental wetland mesocosms. Journal of Geophysical Research: Biogeosciences. 122(11). 2769-2785.
*denotes UMD student author