Elizabeth Boyer

Associate Professor
  
  

327 Hilgard Hall
Berkeley, California 94720
boyer@nature.berkeley.edu
office: 510-643-6679   lab: 510-643-6197   fax:  510-295-2666

     Recent publications     

Watershed hydrology, ecosystems, biogeochemistry, water quality modeling, watershed management.

My research focuses on coupled hydrological and ecological processes that affect water quality (e.g., nutrients, sediments) and water quantity (e.g., streamflow and water yield) issuing from watersheds. I am interested in how human activities (e.g., forest management, energy & food production), environmental changes (e.g., climate, land-use) and disturbances (e.g., droughts, floods & fire) affect watershed responses. Understanding factors affecting conditions and trends in surface waters and the associated ecological effects is increasingly important. Such work provides a scientific basis for design and implementation of policies and land management programs to mitigate the effects of pollution, and to protect, conserve, and restore surface waters.

Much of my work addresses hydrological and biogeochemical processes affecting two primary nutrients that are basic elements of water quality: nitrogen and organic carbon. Cycles of nitrogen, carbon, and water are tightly linked in both terrestrial and aquatic ecosystems, calling for integrated watershed studies. Literally the stuff-of-life, nutrients are ubiquitous in the environment, are needed to sustain growth of plants and animals, and are influenced by the pervasive feedbacks between hydrology and ecology. For example, the distribution of vegetation (i.e., carbon produced by photosynthesis) and its productivity (which often is limited by nitrogen availability) are related to climatic gradients associated with the distribution of precipitation (i.e., hydrology). In turn, vegetation affects both precipitation and temperature through evapotranspiration. Further, changes in the species, density, and pattern of vegetation in a watershed can have profound impacts on the amount, timing, and quality of water levels and streamflow. Hydrological and ecological processes interact over many spatial scales, and water quality in freshwater ecosystems is largely dependent upon biogeochemical cycles of nutrients.

Though nutrients are associated with healthy watersheds and the provision of ecosystem services, they also can act as pollutants. Commonly described as "too much of a good thing," it is the over-abundance of nutrient loadings that can lead to negative environmental effects. Nutrient inputs to landscapes and receiving waters have vastly increased in recent decades, and are affected by anthropogenic activities in agricultural lands (e.g., fertilization, crop & animal production, irrigation), forested lands (e.g., forest management, rural development), and urban lands (e.g., energy production, stationary source emissions, septic & sewage). Elevated nutrient loadings are associated with a host of severe environmental consequences, and pollution of surface waters with nutrients are among the most widespread water quality problems in the world.

Alexander RB, EW Boyer, RA Smith, GE Schwarz, and RB Moore (2007). The role of headwater streams in downstream water quality. Journal of the American Water Resources Association, 43(1):41-59.

Boyer EW, RB Alexander, WJ Parton, CS Li, K Butterbach-Bahl, SD Donner, RW Skaggs, and S Del Grosso. (2006). Modeling denitrification in terrestrial and aquatic ecosystems at regional scales. Ecological Applications, 16(6): 2123–2142

Boyer EW, RW Howarth, JN Galloway, FJ Dentener, PA Green, and CJ Vörösmarty (2006). Riverine nitrogen export from the continents to the coasts. Global Biogeochemical Cycles, 20, GB1S91, doi:10.1029/2005GB002537.

McClain ME, EW Boyer, CL Dent, SE Gergel NB Grimm, PM Groffman, SC Hart, JW Harvey, CA Johnston, E Mayorga, WH McDowell, G Pinay (2003). Biogeochemical hot spots and hot moments at the interface of terrestrial and aquatic ecosystems. Ecosystems 6(4): 301-312

Boyer EW, CL Goodale, NA Jaworski & RW Howarth (2002). Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern USA. Biogeochemistry, 57:137-169.

McKnight DM, EW Boyer, P Doran, PK Westerhoff, T Kulbe, and D Andersen (2001). Spectrofluorometric characterization of aquatic fulvic acid for determination of precursor organic material and general structural properties. Limnology and Oceanography, 46: 38-48.