HR: 1330h
AN: NB33L-12    [Abstracts]
TI: Trends in Dissolved Organic Carbon Concentrations in Intermittent Prairie Streams
AU: * Eichmiller, J
EM: eich@ksu.edu
AF: Kansas State University, Division of Biology 232 Ackert, Manhattan, KS 66506 United States
AU: Dodds, W K
EM: wkdodds@ksu.edu
AF: Kansas State University, Division of Biology 232 Ackert, Manhattan, KS 66506 United States
AB: Discharge and dissolved organic carbon (DOC) data from headwater streams of Konza Prairie Research Natural Area, Kansas. Samples taken 3 times per week during periods of flow from 1995-2001 revealed three major trends in DOC dynamics. Streams exhibited low surface water DOC concentrations (1.02 mg/L, SD 0.64, n=589) at baseflow, high storm flows following a drought or low flow period caused 3-5 fold increases in DOC (up to 6.9 mg/L), and gradual resumption of stream flow following drought yielded increased DOC concentrations over several days of continuous flow. We propose a model in which hydrologic flow paths explain observed trends in DOC dynamics. We assume three compartments, soil, groundwater and streamwater. When water flows slowly from the soil to the stream through groundwater, microbial activity lowers DOC concentration. When floods occur, DOC moves rapidly from soil to stream channels. When flow resumes slowly after a dry period, soil DOC is increasingly flushed through the system leading to gradual increases in DOC. The proposed model for DOC dynamics provides a framework for future research and suggests the potential importance of hydrologic flow paths to DOC concentration in prairie streams.
DE: 1845 Limnology
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly