1 Challenge: multiple input pathways Challenge: multiple - PDF document

Nitrogen sources to Collaborators rivers & estuaries of New York Rich Alexander, U.S. Geological Survey, VA Jim Galloway, University of Virginia Christy Goodale, Cornell University, NY Bob Howarth, Cornell University, NY Kate Lajtha, Oregon State University, OR Bernhard Mayer, University of Calgary, Canada Keith Paustian, Colorado State University, CO Greg Schwarz , U.S. Geological Survey, VA Sybil Seitzinger, Rutgers University, NJ Dick Smith, U.S. Geological Survey, VA Nico vanBreemen, Wageningen, the Netherlands Elizabeth W. Boyer, State University of New York, Syracuse Robert W. Howarth, Cornell University, Ithaca, NY Richard B. Alexander, U.S. Geological Survey, Reston, VA Outline The cascading • Need to understand importance of atmospheric N in effects of N terrestrial & aquatic ecosystems pollution -- • Challenges for estimating atmospheric N deposition Significance of • Approaches for quantifying significance of atmospheric N atmospheric N inputs & their fate deposition? • Implications & Future Directions Impacts table from Driscoll et al. 2003, Hubbard Brook Research Foundation Challenge: multiple sources of N emissions Challenges for understanding atmospheric N inputs to terrestrial & aquatic ecosystems • Multiple reactive N species • Multiple emissions sources • Multiple transport pathways • Quantifying atmospheric N deposition NO x Emission Data from EPA National Air Pollution Emission Trends 1

Challenge: multiple input pathways Challenge: multiple atmospheric N species • Reduced nitrogen, NH x Typically dominated by ammonia species (e.g., NH 3 and NH 4 + ) • Oxidized nitrogen, NO x Composed primarily of nitrogen oxide species, ­ and representing primarily nitric oxides (NO 3 HNO 3 ) and nitrogen dioxide (NO 2 ) • Wet deposition is the fraction contained in precipitation— predominantly rain and snow. • Organic nitrogen, AON • Dry deposition is the fraction deposited in dry weather through such processes as settling, impaction, and adsorption. How much N deposition does NY receive? Quantifying Atmospheric Deposition Inorganic nitrogen wet deposition at monitoring sites National Atmospheric Deposition NADP­NTN Program National Trends Network (NADP­NTN): Wet deposition monitoring, designed to determine geographical patterns & long­term trends 2002 in precipitation chemistry. 9 active sites in NY; most since ~ 1980. AIRMoN Atmospheric Integrated Research Monitoring Network (AIRMoN): Wet deposition monitoring, designed to determine daily and storm­event trends. 1 site in NY since 1992. CASTNET Clean Air Status and Trends Network (CASTNET): provides dry deposition & ground­level ozone monitoring data. 2+ active sites in NY since ~ 1990. Data from National Atmospheric Deposition Program ­ National Trends Network How much N deposition does NY receive? How much N deposition does NY receive? Inorganic nitrogen wet & dry deposition Inorganic nitrogen wet deposition at monitoring sites 14 mean 12 median N deposition, kg/ha ny08 10 ny10 ny20 8 ny22 6 ny52 ny65 4 ny68 ny98 2 ny99 0 Data from Clean Air Status and Trends Network, 1980 1985 1990 1995 2000 Monitoring station at Connecticut Hill, CTH110 Data from National Atmospheric Deposition Program ­ National Trends Network 2

Challenge: scaling up from monitoring sites Challenge: underestimating atmospheric N? How to estimate dry deposition at wet­only sites? • Deposition in coastal, urban, & How to interpolate sparse data over space & time? agricultural areas? Monitoring in in rural areas, to assess relationships Ollinger et al. w/ Lovett & Rueth 1999 K 14 - 1 Ollinger et al. 1993 AN between regional pollution and -1 yr Lovett & Lindberg 1993 ( SA C deposition patterns. Total inorganic N deposition, kg ha 12 ATM3 model, Dentener 2000 ME R HU D C ON ( ( ( ( MOH • Underestimating ammonium? ( ( 10 B LA Comparisons of AIRMON and D E L NADP data suggest loss of wet NH x 8 SUS ( S C H ( species due to biological activity in ( 6 t collection buckets during week­long storage. Underestimated >15%, 4 Meyers et al. 2001 2 • Underestimating atmospheric Organic N? ~30% of total in 0 Connecticut Hudson Mohawk Delaware Susquehanna northeast, Neff et al. 2003 Boyer et al. 2002 Challenge: quantifying agricultural volatilization Approaches to quantifying How much is transported long­range significance & fate of atmospheric N versus re­deposited locally? AN in terrestrial & aquatic ecosystems SAC MER H UD CON ( ( ( MOH ( 10 animal waste, Cass et al. 1982 ( animal waste, Asman 1990 BLA -1 animal waste, van der Hoek 1998 DEL -1 y r animal waste, Krus et al. 1989 8 S U S NH x -N volatilization, kg ha animal waste, Moller & Schieferdecker 1989 ( animal waste, Buijsman et al. 1987 SCH ( animal waste, ApSimon et al. 1987 ( animal waste, Bouwman et al. 1997 6 animal waste, Lee 1994 animal waste, Battye et al. 1994 fertilizer, Battye et al. 1994 4 • Mass balance model: TNNI 2 • Empirical model: SPARROW 0 Connecticut Hudson Mohawk Delaware Susquehanna Boyer et al. 2002 Major Watersheds of NY Mass balance model: total net N inputs • Quantify new inputs of N (N that is newly fixed within, or newly transported into, each region) – atmospheric deposition – application of nitrogenous fertilizers – biological N fixation by crops – net import or export of N in food & feed • Quantify outputs of N in streamflow • Quantify fate of remainder… Howarth et al. 1996, Boyer et al.2002 3

Quantified Mass balance model: fate of N inputs? N inputs, storages, and losses for • Uptake by vegetation 16 coastal • Storage in soils or groundwater watersheds in the northeast USA • Conversion and loss to atmospheric forms through denitrification & volatilization • Export in streamflow Boyer et al. 2002 Primary data sources Watershed land use, from north to south • Topography & catchment boundaries delineated from USGS 1° DEMs 100% • National Land Cover Database of the Multi­Resolution Land Characteristics Interagency Consortium (MRLC). Watershed Land Use 80% • Population data & characteristics from the Census Bureau, 1990 • Discharge and N concentration data from USGS (Alexander et al. 1998) 60% • Atmospheric deposition from the National Atmospheric Deposition Program 40% • Nitrogenous fertilizer use from USGS spatial database on agricultural chemical use in the US (Battaglin & Goolsby 1994) 20% • Livestock and crop information, for calculating agricultural transfers of N in food and feedstocks, from the 1992 USDA Census of Agriculture forest agricultural urban water & wetl. other 0% • Forest growth data from USDA Forest Service’s Forest Inventory and POT Total PEN KEN AND SAC MER CHA BLA CON HUD DEL SCH SUS RAP JAM MOH Analysis (FIA) program • River reach characteristics from USGS national hydrologic dataset Boyer et al.2002 Mass balance model Mass balance model Total N inputs in 16 northeastern catchments Total N inputs to catchments are related to riverine export Net import in feed 2 /yr 2000 Net import in food Northeastern USA Fertilizer use 2 =0.62 6000 y =0.26x; R N export in streamflow, kg/km Agricultural N2 fixation Net atmospheric deposition 1600 5000 Forest N2 fixation /yr 2 Nitrogen, kg/km 4000 1200 Howarth et al. 1996: NE USA 3000 800 2000 1000 400 0 0 -1000 JAM AND SAC CHA MOH SUS RAP PEN KEN MER BLA CON HUD DEL SCH POT 0 2000 4000 6000 2 /yr Total N inputs, kg N/km Boyer et al.2002 Boyer et al.2002 4