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The Near‐Stream Zone is a Source of Nitrogen in a Swedish Forested Catchment
Author(s) -
Fölster Jens
Publication year - 2000
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2000.00472425002900030026x
Subject(s) - environmental science , hydrology (agriculture) , leaching (pedology) , nitrate , ammonium , surface runoff , soil water , drainage basin , surface water , environmental chemistry , ecology , chemistry , soil science , geology , environmental engineering , geography , geotechnical engineering , cartography , organic chemistry , biology
Most Swedish forests efficiently retain N from deposition and runoff N can be expected to originate from the near‐stream zone. Nitrogen leaching from this region is low, but still may be of ecological relevance (e.g., in oligotrophic lakes). In the present study the function of the near‐stream zone with respect to N chemistry in stream water of a small pristine catchment in central‐south Sweden was investigated. The study included ground water, soil water, and stream water sampling. The aim was to explain the variation in N species in stream water with hydrological flow paths and the spatial and temporal variation in N in ground water and soil water. Nitrate and ammonium concentrations were negligible in ground water and soil water at most locations. When nitrate occurred, it was usually at concentrations below 100 µg N L −1 and related to higher pH and aerobic conditions. Ammonium was detected in anaerobic locations at stable concentrations up to 200 µg N L −1 . The near‐stream zone was the main source of organic N entering the stream where the median concentration was 240 µg L −1 . Nitrate occurred only occasionally in stream water at concentrations around 100 µg N L −1 and then probably originated from near‐stream pre‐event water. The only significant ammonium concentrations were detected during a spring flow episode and there were indications of flushing of organic matter of microbial origin. The importance of within‐catchment variation for understanding leaching processes in forested catchments is discussed.