HR: 14:15h
AN: NB23E-04 INVITED     [Abstracts]
TI: Land-use Impacts on Nitrate Removal and Retention in six Kansas Streams
AU: * OBrien, J M
EM: jobrien@ksu.edu
AF: Kansas State University, 232 Ackert Hall Division of Biology, Manhattan, KS 66506 United States
AU: Dodds, W K
EM: wkdodds@ksu.edu
AF: Kansas State University, 232 Ackert Hall Division of Biology, Manhattan, KS 66506 United States
AU: Wilson, K C
EM: kymw@ksu.edu
AF: Kansas State University, 232 Ackert Hall Division of Biology, Manhattan, KS 66506 United States
AU: Murdock, J N
EM: murdockj@ksu.edu
AF: Kansas State University, 232 Ackert Hall Division of Biology, Manhattan, KS 66506 United States
AU: Eichmiller, J J
EM: eich@ksu.edu
AF: Kansas State University, 232 Ackert Hall Division of Biology, Manhattan, KS 66506 United States
AB: We used short-term ¹⁵N-nitrate tracer additions to determine the rates of nitrogen transformations in six low-order Kansas streams draining prairie, agricultural, and urban lands. Baseline nitrate concentrations ranged from 0.001 to 3 mg/L nitrate-N, and were highest in the two urban streams and lower in the agricultural and prairie streams. A linear relationship existed between stream nitrate concentration and uptake rate (p > 0.001), uptake length (p > 0.001) and nitrification (p > 0.001). Denitrification made up only a small portion of uptake in all of the streams. These relationships do not suggest a saturation of nitrate uptake within the range of concentrations encountered in this study. Regeneration of tracer DIN was minimal after 1, 3, and 7 days. Increases in uptake in the urban streams appear to be attributable to increased autotrophic assimilation and denitrification. Land-use within the watersheds influenced stream nitrate concentration and subsequently the rates of nutrient cycling within the streams.
DE: 1845 Limnology
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly