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Seasonal variation in nutrient retention during inundation of a short‐hydroperiod floodplain
Author(s) -
Noe Gregory B.,
Hupp Cliff R.
Publication year - 2007
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.1035
Subject(s) - floodplain , environmental science , nutrient , hydrology (agriculture) , flood myth , overbank , sediment , snowmelt , ecology , surface runoff , geology , geography , paleontology , geotechnical engineering , archaeology , facies , structural basin , biology
Floodplains are generally considered to be important locations for nutrient retention or inorganic‐to‐organic nutrient conversions in riverine ecosystems. However, little is known about nutrient processing in short‐hydroperiod floodplains or seasonal variation in floodplain nutrient retention. Therefore, we quantified the net uptake, release or transformation of nitrogen (N), phosphorus (P) and suspended sediment species during brief periods (1–2 days) of overbank flooding through a 250‐m floodplain flowpath on the fourth‐order Mattawoman Creek, Maryland U.S.A. Sampling occurred during a winter, two spring and a summer flood in this largely forested watershed with low nutrient and sediment loading. Concentrations of NO 3 −increased significantly in surface water flowing over the floodplain in three of the four floods, suggesting the floodplain was a source of NO 3 − . The upper portion of the floodplain flowpath consistently exported NH 4 + , most likely due to the hyporheic flushing of floodplain soil NH 4 + , which was then likely nitrified to NO 3 −in floodwaters. The floodplain was a sink for particulate organic P (POP) during two floods and particulate organic N and inorganic suspended sediment (ISS) during one flood. Large releases of all dissolved inorganic N and P species occurred following a snowmelt and subsequent cold winter flood. Although there was little consistency in most patterns of nutrient processing among the different floods, this floodplain, characterized by brief inundation, low residence time and low nutrient loading, behaved oppositely from the conceptual model for most floodplains in that it generally exported inorganic nutrients and imported organic nutrients. Published in 2007 by John Wiley & Sons, Ltd.