Open AccessStorm event exports of dissolved organic nitrogen (DON) across multiple catchments in a glaciated forested watershed
Author(s) -
Inamdar Shreeram P.,
Mitchell Myron J.
Publication year - 2007
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006jg000309
Subject(s) - throughfall , baseflow , environmental science , hydrology (agriculture) , dissolved organic carbon , watershed , wetland , storm , drainage basin , streamflow , environmental chemistry , ecology , geology , soil water , soil science , chemistry , geography , oceanography , geotechnical engineering , machine learning , computer science , cartography , biology
Storm event patterns of dissolved organic nitrogen (DON) were studied for multiple events across four catchments (1.6–696 ha) in a forested, glaciated watershed in western New York State. Highest concentrations of DON in the watershed were recorded for litter leachate followed by throughfall. Storm event concentrations of DON consistently peaked at or before peak discharge while dissolved organic carbon (DOC) concentrations peaked on the hydrograph recession limbs. Concentrations of DON in stream water were derived from throughfall and litter layer while the DOC expression was attributed to throughfall, litter, and the flushing of the mineral soil by a rising water table. Temporal patterns of ammonium (NH 4 + ) concentrations during events consistently matched those of DON indicating similar sources and flow paths. A previously validated end‐member mixing analysis (EMMA) for NO 3 − failed to predict the DON concentrations observed in streamflow. DON concentrations and DON as % of total dissolved nitrogen (TDN) differed considerably between baseflow (% DON: 6 to 19%) and storm events (% DON: 6 to 64%). DON concentrations and % DON of TDN increased with catchment size and amount of saturated/wetland areas. A wetland catchment that consistently yielded high storm‐event DOC concentrations produced variable amounts of DON, indicating a decoupling of DOC and DON dynamics in the wetland. Our study suggests that storm events and watershed characteristics, especially the proportion of saturated and wetland areas, may have a greater influence on DON exports than atmospheric N deposition.