HR: 09:15h
AN: B51F-06    [Abstracts]
TI: Nitrogen inputs, ouptut, and retention in a coastal suburban basin
AU: * McDowell, W H
EM: bill.mcdowell@unh.edu
AF: University of New Hampshire, Dept. of Natural Resources, Durham, NH 03824
AU: Daley, M L
EM: mldaley@cisunix.unh.edu
AF: University of New Hampshire, Dept. of Natural Resources, Durham, NH 03824
AU: Gettel, G
EM: gretchen.gettel@unh.edu
AF: University of New Hampshire, Dept. of Natural Resources, Durham, NH 03824
AB: Understanding the biogeochemistry of suburban basins is becoming increasingly important due to the rapidly accelerating suburban sprawl in many parts of the US. In southeastern New Hampshire, population density is expected to increase by 50% over 20 years, and most of the development will occur as low-density suburban home lots with wells and on-site waste disposal. We measured the N inputs, outputs, and loss/storage in a 470 sq km basin, the Lamprey River of coastal New Hampshire. Atmospheric deposition and food imported into the basin were both significant inputs, and totaled 13 kg/ha/yr. Output was 0.6 kg/ha/yr, for a net loss/retention of 95% of inputs. Net retention among various sub-watersheds of the Lamprey ranged from 50 to 98%. Because the Lamprey river basin contains a high proportion of wetlands (14% wetlands and open water), has some water courses that undergo periodic oxygen depletion, and has high levels of dissolved organic carbon in surface waters (6 mg/l), in-stream and wetland denitrification may be a major loss pathway for N in the basin. Results from a study of riparian zone biogeochemistry suggest that riparian denitrification may also be a significant loss pathway. Accelerating suburbanization may greatly increase N delivery to the coast if it shortens hydrologic flow paths and decreases wetland coverage while increasing N inputs.
DE: 0400 BIOGEOSCIENCES
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
SC: Biogeosciences [B]
MN: Fall Meeting 2005