Nitrogen dynamics in runoff from two small heathland catchments representing opposite extremes with respect to climate and N deposition in Norway

• Main Authors: Øyvind Kaste, Brit Lisa Skjelkvåle
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2002
• Subjects: Key words; catchments; surface water; nitrogen deposition; nitrate leaching; climate; hydrology; Arctic; Norway; Øygard; Northern Norway
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.371.8170; http://hal.archives-ouvertes.fr/docs/00/30/46/67/PDF/hess-6-351-2002.pdf

Effects of contrasting climatic conditions and nitrogen (N) deposition levels on streamwater N dynamics are assessed at two small heathland catchments; Dalelva in northern Norway (69oN) and Øygard in southwestern Norway (58oN). The study comprises 11 years of data on climate, hydrology and N inputs/outputs from Dalelva and 8 years of corresponding data from Øygard. Both sites are comparable in catchment size, geology and land cover characteristics, but have large differences in climate and N deposition. Dalelva is characterised by a cold, arctic climate and low N deposition (2-3 kg N ha –1 yr –1), whereas the Øygard site has a more mild, humid climate with much larger N deposition (13–19 kg N ha –1 yr –1-). Streamwater nitrate (NO) concentrations at Dalelva generally were negligible during the growing season, but showed 3 a steady increase during the dormant season until a maximum of 40-100 µg N L –1 was reached just before snowmelt. At onset of the snowmelt flood, NO concentrations decreased momentarily to very low levels, suggesting that N eluted from the seasonal snowpack to a great extent 3 was infiltrated and immobilised in the soils. At Øygard, flood peaks occurred frequently during all seasons, and usually there was no distinct spring flood. A lack of clear dilution effects from floods on streamwater NO concentrations may indicate a relatively high NO3 leaching 3