| Institution: | District of Columbia Department of Energy and Environment | 
            
            
		| Department: | Natural Resources | 
            
      
      | Expertise: | Agricultural Runoff, Biogeochemistry, Nutrient Cycling, Nutrient Pollution, Water Quality | 
            
		| Chesapeake Management Areas: | Water Quality, Toxic Contaminants | 
	
	      
      
            
		| Research interests: | Resolving sources, history, and fate of nitrogen in groundwater and streams; application of environmental tracers and isotopes to determine transport times and reaction rates of dissolved constituents; environmental isotope forensics; water quality effects of agriculture and wastewater disposal in different climatic and hydrogeologic settings. | 
            
      		| Email: | jkbohlke@usgs.gov | 
            
            | Web Address: | www.usgs.gov/staff-profiles/john-karl-bohlke | 
            
            | Phone Number: | 703-648-6325 |