Boyer Elizabeth

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  • Article
    Intentional versus unintentional nitrogen use in the United States : trends, efficiency and implications
    (Springer, 2012-10-13) Houlton, Benjamin Z. ; Boyer, Elizabeth ; Finzi, Adrien C. ; Galloway, James ; Leach, Allison ; Liptzin, Daniel ; Melillo, Jerry M. ; Rosenstock, Todd S. ; Sobota, Daniel J. ; Townsend, Alan R.
    Human actions have both intentionally and unintentionally altered the global economy of nitrogen (N), with both positive and negative consequences for human health and welfare, the environment and climate change. Here we examine long-term trends in reactive N (Nr) creation and efficiencies of Nr use within the continental US. We estimate that human actions in the US have increased Nr inputs by at least ~5 times compared to pre-industrial conditions. Whereas N2 fixation as a by-product of fossil fuel combustion accounted for ~1/4 of Nr inputs from the 1970s to 2000 (or ~7 Tg N year−1), this value has dropped substantially since then (to <5 Tg N year−1), owing to Clean Air Act amendments. As of 2007, national N use efficiency (NUE) of all combined N inputs was equal to ~40 %. This value increases to 55 % when considering intentional N inputs alone, with food, industrial goods, fuel and fiber production accounting for the largest Nr sinks, respectively. We estimate that 66 % of the N lost during the production of goods and services enters the air (as NO x , NH3, N2O and N2), with the remaining 34 % lost to various waterways. These Nr losses contribute to smog formation, acid rain, eutrophication, biodiversity declines and climate change. Hence we argue that an improved national NUE would: (i) benefit the US economy on the production side; (ii) reduce social damage costs; and (iii) help avoid some major climate change risks in the future.
  • Working Paper
    A science plan for carbon cycle research in North American coastal waters. Report of the Coastal CARbon Synthesis (CCARS) community workshop, August 19-21, 2014
    (Ocean Carbon & Biogeochemistry Program, 2016) Benway, Heather M. ; Alin, Simone R. ; Boyer, Elizabeth ; Cai, Wei-Jun ; Coble, Paula G. ; Cross, Jessica N. ; Friedrichs, Marjorie A. M. ; Goni, Miguel ; Griffith, Peter C. ; Herrmann, Maria ; Lohrenz, Steven E. ; Mathis, Jeremy T. ; McKinley, Galen A. ; Najjar, Raymond G. ; Pilskaln, Cynthia H. ; Siedlecki, Samantha A. ; Smith, Richard A.
    Relative to their surface area, continental margins represent some of the largest carbon fluxes in the global ocean, but sparse and sporadic sampling in space and time makes these systems difficult to characterize and quantify. Recognizing the importance of continental margins to the overall North American carbon budget, terrestrial and marine carbon cycle scientists have been collaborating on a series of synthesis, carbon budgeting, and modeling exercises for coastal regions of North America, which include the Gulf of Mexico, the Laurentian Great Lakes (LGL), and the coastal waters of the Atlantic, Pacific, and Arctic Oceans. The Coastal CARbon Synthesis (CCARS) workshops and research activities have been conducted over the past several years as a partner activity between the Ocean Carbon and Biogeochemistry (OCB) Program and the North American Carbon Program (NACP) to synthesize existing data and improve quantitative assessments of the North American carbon budget.