HR: 1330h
AN: B32B-0382    [PDF]
TI: Dissolved Nitrogen and Phosphorus Export to the Coastal Zone: Early Results From a Global, Multi-element, Multi-form Modeling Approach
AU: * Harrison, J A
EM: harrison@imcs.rutgers.edu
AF: Rutgers University, 71 Dudley Rd., New Brunswick, NJ 08901 United States
AU: Seitzinger, S P
EM: sybil@imcs.rutgers.edu
AF: Rutgers University, 71 Dudley Rd., New Brunswick, NJ 08901 United States
AU: Kroeze, C
EM: Carolien.Kroeze@WIMEK.CMKW.WAU.NL
AF: Wageningen University, P.O. Box 9101 6700 HB Wageningen, Wageningen, 6700 Netherlands
AU: Caraco, N
EM: caracon@ecostudies.org
AF: Institute of Ecosystem Studies, Box AB; Route 44A, Millbrook, NY 12545-0129 United States
AU: Dumont, E
EM: Egon.Dumont@wur.nl
AF: Wageningen University, P.O. Box 9101 6700 HB Wageningen, Wageningen, 6700 Netherlands
AB: In watersheds, spatial variation in nutrient sources and sinks results in spatial variability of nutrient export ratios and nutrient forms, with important implications for estuarine ecosystem response. However, past attempts to model global or regional nutrient exports to the coastal zone in a spatially explicit manner have focused on just one element at a time, and have generally ignored nutrient form. A new modeling initiative, Global NEWS (Global (N)utrient (E)xport from (W)ater(S)heds), constitutes the first attempt to develop an internally consistent, spatially explicit estimate of coastal nutrient loading by multiple elements (N, phosphorus (P), C, and silica (Si)) and multiple element forms (Particulate N, P, C, and Si, dissolved inorganic N, P, and Si, and dissolved organic N, P, and C). Early model results indicate significant regional differences in form and amount of nutrients exported. In this presentation we focus on Global NEWS-based estimates of coastal dissolved inorganic and organic N (DIN and DON) and dissolved inorganic P (DIP) loading, and on how DIN:DIP and DIN:DON ratios both vary by region and are influenced by human, edaphic, biotic, and climatic factors. Early model results are consistent with the hypothesis that DIN exports constitute the majority of dissolved N export from regions with heavy human influence while DON dominates the dissolved N exported from regions with relatively little human influence. Model results also show a strong correlation between DIN and DIP export (R$^{2}$ = 0.67).
DE: 0400 Biogeosciences
DE: 1871 Surface water quality
SC: Biogeosciences [B]
MN: 2003 Fall Meeting