DIEL PATTERNS IN DISSOLVED ORGANIC MATTER IN A FORESTED HEADWATER CATCHMENT IN MARYLAND
Baseflow samples were collected hourly for 72 hours from 4 sites within a 79 ha forested, headwater catchment in the Piedmont Region of Maryland. Additionally, in stream UV and fluorescence sensors measured temperature, pH, conductivity, turbidity, nitrate-N, DOC, dissolved oxygen, and fluorescence of dissolved organic matter every 15-30 minutes. Subhourly measurements of discharge and groundwater elevation were also collected. Grab samples were analyzed for major cations and anions, DOC, and excitation-emission matrices- an indicator of DOM quality.
The results of this study suggest that during the data collection time period, DOC and nitrate-N concentrations did not exhibit as strong of a diel pattern as dissolved oxygen, which showed a consistent diel pattern at all 4 sites. Conversely, data from earlier months indicate that DOC and nitrate-N diel patterns may be stronger during dry periods, indicating potential for future investigation and interpretations.