Effects of land use on northern boreal streams : a study of stream nutrient patterns in Röbäcksdalen, Umeå

• Main Author: Stenlund, Emma
• Format: Others
• Language: English
• Published: Umeå universitet, Institutionen för ekologi, miljö och geovetenskap 2020
• Subjects: nutrients; land use; agriculture; stream chemistry; discharge; Natural Sciences; Naturvetenskap
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-171876

Nutrient loading to aquatic and marine ecosystems is a topic of interest, especially as the human population continues to grow and land use changes. Here, I examined the seasonal variability and relative amounts of different forms of nitrogen (N) and phosphorous (P) from four sites at Röbäcksdalen (Umeå, Västerbotten), an area influenced by both agriculture and partial urbanization. In addition, I studied how nutrient concentration varied with discharge during snowmelt. Overall, the results show that the seasonality of nutrient concentration did not differ drastically from what is expected in more pristine boreal catchments. However, the concentrations of dissolved inorganic N (DIN) and phosphate (PO4) were elevated. Land use activities in Röbäcksdalen also appear to be influencing inorganic N inputs to streams to a greater degree than inputs of inorganic P. Comparisons with more pristine boreal streams also reveal a fundamental change in the composition of the stream N pool, with greater dominance of DIN within the catchment. This pattern is likely due to inputs of nutrients in excess of biotic demand. Lastly, the results of the concentration-discharge analysis from Röbäcksdalen indicate that hydrological forcing rather than soil processes control the supply of nutrients to these streams during snowmelt. With concentrations being high, this also indicates that a considerable increase in the flux of nutrients from the area is expected with increased discharge.